Students partition whole numbers up to 20 into equal groups (e.g., dividing 12 into 2 groups of 6, 3 groups of 4, etc.) and record those results on activity sheets. The skills list explicitly asks students to write an equation to express an even number as a sum of two equal addends. Students are also prompted to count by 2s, use tally marks, and solve sharing problems sometimes without manipulatives, which can involve informal mental counting.

Students create and name arrays (e.g., 4 by 3, 2 by 6) and use them to write repeated-addition number sentences such as 3+3+3+3=12 and 4+4+4=12. Students make arrays for given totals (8, 12, 16, 20, 24) and write two corresponding addition sentences (e.g., 2+2+2+2=8 and 4+4=8). Students use counters, sticky-note number labels, dice-rolled rows/columns, and an online practice game to generate and solve addition sentences from arrays.

Students practice multiple addition strategies: they show and write addition sentences for numbers like 9 and 15 using arrays, tally marks, dice, dominoes, number lines, and an abacus. Students use number lines to add (for example 4 + 3 -> 7 and problems on a 0–20 number line), represent and count sums on the abacus (examples include 5+5=10, 8+7=15, 6+8=14), and complete repeated dice rolls to generate and record turn-around facts (commutative property) such as 4+6 and 6+4 ten times. Students are prompted to name addends and sums, list ways to add, and are encouraged to use their "brain" (mental strategies) when manipulatives are not available.

Students practice adding one- and two-digit numbers in concrete and visual ways (e.g., drawing to find sums 3+5, 4+2, 6+3; using counters, abacus, tally marks). Students solve and create addition word problems (Clues to Addition, I Can Make Addition Problems) and identify addition clue words to decide when to add. Students play addition games that require finding sums up to 18 (beanbag toss with bowls labeled 10–18) and determine missing addends (2 + ___ = 5, missing-addend beanbag toss). Students work with addition flashcards up to 20 and sort facts into stacks to identify which two one-digit sums they have memorized and which need practice.

Students solve many subtraction problems within 20 using concrete and pictorial strategies: Activity 2 asks students to compute 6 - 3 = ? using a number line, counters, pictures, fingers, or an abacus and to try multiple approaches. Student activity pages include sets of subtraction problems (e.g., 18-7, 14-7, 18-6, 12-4, 15-9, 10-5, 9-6) that students solve with objects, number lines, and fingers. In Activity 3 (Bowling for Differences) students quickly determine differences for orally read subtraction sentences (10-9, 8-1, 6-4, etc.) and select the corresponding result under time/pressure.

Students solve multiple subtraction word problems by writing completed number sentences (Activity 1 and Student Activity Pages) and use strategies such as fingers, drawings, counters, and number lines to find differences. Activity 4 asks students to use mental strategies (‘‘use his brain (or fingers)'') to determine how many items remain without recounting. The Wrapping Up section directs students to practice addition flashcards and to add subtraction flashcards to 20 as part of their fact practice.

Students practice mental-addition strategies: activities teach the identity/zero property (Activity 1 and "Working With Zero" sheet), doubles (Activity 3 and "Doubles" page), doubles plus one and near-doubles (Activity 4 and the foldable), and making tens/using 5 (Activities 5–7 and related sheets). Students are prompted to use flashcards for rapid recall (Activity 2 and Wrapping Up) and can use the linked timed/untimed online quizzes to practice addition facts. Optional games (Fishing for 10 and Taking 10) give students repeated practice using addition and, in one game, subtraction to form 10s.

Students complete timed practice on the "Fact Power 1" sheet containing 30 addition/subtraction number sentences that focus on doubles, doubles-plus-one, zero, and making tens. Students identify and generate all four fact-family sentences from three numbers using dominoes and a Fact Family worksheet, and they make and use triangular fact-family cards that cover sums up to 20. Students play matching and concentration games that require matching number sentences to sums and use online games and flashcards to practice addition and subtraction facts to 20 while recording time and accuracy on a Fact Power record sheet.

Students complete the "Fact Power 2" timed sheet with 30 addition and subtraction facts to 20 and record times to build speed. Students play "Brain vs. Calculator" using flashcards to 20, answering mentally to compete with a calculator and keeping tally scores. In Activity 3, students generate all addition sentences that make 5 and are prompted to use turn-around facts and consider what 0 does to a sum. The A Day at the Fair problems require students to add and subtract ticket amounts within 20 and to use their "fact power" when solving one- and two-step problems.

Students complete timed "Fact Power" drills (Fact Power 3 and Fact Power 4) that present many addition and subtraction problems arranged in grids, and students record times on a "Fact Power Record" sheet to beat previous times. Students practice with flashcards, sort them by mastery, and repeat them several times to build speed and recall. Students must include explicit addition and subtraction expressions and answers in their "Mathematical Ocean Adventure" story (including two addition and two subtraction problems) and record answers on an answer sheet. The project rubric explicitly checks for "Correct math" and the required number of addition and subtraction problems.

The introduction directs giving 10 random addition and subtraction flashcards with sums no higher than 20 and asks the child to go through them quickly, making a pile for facts known instantly and a pile for those not known. It instructs placing unknown facts in a bag to revisit and practice over the course of the unit and notes that minuends or first numbers in subtraction are no higher than 20. The lesson states there are 121 basic addition facts using numbers 0–10 and sets the goal for the child to know all of these facts by the end of the year.

The lesson directs an adult to "give your child 10 more random addition and subtraction flashcards" and to have the child "continue the process of determining which ones she knows". It instructs the child to review the flashcards she didn't know from the previous lesson. These sentences explicitly ask students to practice addition and subtraction facts with flashcards.

The Introduction asks the child to complete 10 random addition and subtraction flashcards and to review the ones not yet known, providing practice with basic arithmetic facts. The Wrapping Up asks the child to select two number cards (1–100) and compare which is greater or less, giving additional number sense practice. The lesson also includes counting practice (by 2s from 40 to 80 and by 10s to 100), which supports numeric fluency generally.

The lesson instructs students to do "10 more random addition and subtraction to 20 flashcards" and to "use the same process she's been using to practice her math facts and build her 'fact power.'" It also tells students to keep unknown flashcards in a bag to focus practice and later says to "give your child time to practice her addition and subtraction flashcards." The introduction includes a brief review of counting by 5s from 50 to 100 as a number sense warm-up.

Students are asked in Activity 4 to tally shapes, write totals, and answer questions such as "How many triangles and circles did you find altogether?" and "What's the difference between the number of squares and the number of rectangles that you found?", which requires them to add and subtract counted quantities. The Introduction asks the child to "continue working on his 'fact power' by going through the collection of flashcards" and to practice 10 more random ones, which implies practice of arithmetic facts.

Students are given time to practice 10 random addition and subtraction flashcards and to review flashcards they still need to master. They are reminded and asked to use specific mental strategies (turn-around/commutative property, doubles, doubles plus one/two, fact families, making 10, using two fives) while practicing. They are encouraged to sort flashcards by strategy and practice facts with those strategies in mind.

Students are instructed to spend 10 minutes going through as many addition and subtraction flashcards as they can, including facts they already know and those they are still working on. The flashcard activity explicitly targets basic addition and subtraction fact practice. This provides direct practice with one-digit addition and subtraction facts.

Students read and use a "Basic Addition Strategies" sheet that explicitly includes Doubles, Doubles Plus 1, Making 10s, and Fact Families and are asked to write additional examples for each strategy. Activities ask students to use doubles-plus-one to compute 8+7 and to solve small mental addition problems (for example, 17+30 solved by counting tens or by adding ones first). The Race to 100 game has students add dice rolls (sums often under 12), compose tens, and answer questions about the sums and how many are needed to make the next ten.

Students draw number cards and add them, with explicit prompts to use mental math and place-value reasoning. In Activities 1 and 2 students practice mental 'take-and-give' strategies to make tens for sums such as 9+6, 9+7, 8+7, 8+8 and are asked to solve similar two-addend problems mentally before checking with an abacus. The student pages and the 'Using Addition Strategies' sheet include single-digit addition problems (e.g., 3+7, 9+6, 8+5, 8+8) and ask students to write answers and explain which strategies they used.

Students practice and are asked to solve many subtraction problems within 20 (e.g., 12-5, 10-4, 8-7, 6-3, 5-4) using number lines, counting back, and counting up. The materials explicitly teach and prompt use of mental strategies such as counting back, counting up, using doubles/half facts, neighbors, and the role of zero. The lesson also asks students to try solving some subtraction problems mentally and to explain which strategies they used.

Students are asked to put two pieces of straw together to show 9 inches (for example, 3 + 6 or 4 + 5), which requires adding two one-digit numbers. Students answer questions that add or subtract one inch from a drawn line (e.g., "How long will this line be if I add another inch?" and "How long will this line be if I erase one inch?"), practicing simple addition and subtraction. Students also perform counting and occasional addition tasks in the wrap-up (counting by tens and adding 20 to a number), indicating some exposure to addition operations.

Students draw number cards 1–10, measure and cut ribbon pieces of those exact lengths, and then pick two pieces and measure them to write subtraction sentences such as "9 in. - 7 in. = 2 in." Students complete a kitchen measurement table and are asked to calculate differences in length and "write a subtraction sentence and calculate the difference." Students also practice counting sequences on number grids (counting by 2s and 5s) which reinforces number-fact familiarity.

Students write number sentences and compute sums and differences in the Measurement Problems activity (e.g., 3 + 6, 4 + 6, 11 - 5, 1 + 2 + 3, 12 - 9, 15 - 8, 29 - 26). The activity directions ask students to find sums or differences and to label units, and they may use counters or an abacus or draw pictures to solve the problems. Several word problems use one-digit addends and subtrahends or produce results within 20 (for example 3+6=9, 4+6=10, 11-5=6, 15-8=7).

Students are asked to use mental math tricks explicitly (the text says to "encourage him to use mental math tricks" and mentions "the nines and eights tricks"). Students practice composing 10 and exchanging ones for a ten when problems require it (examples: composing 10 when adding 37+34 and the 1+9 example in Activity 4). Students use the abacus to model adding ones and tens and to mentally check sums after composing or exchanging beads.

Students draw two number cards (1–99), create an addition sentence and a subtraction sentence with the numbers, write each on grid paper, and find the sum and the difference. The text tells students to do this without using materials (encouraging mental work) and to repeat the process multiple times.

The Introduction requires students to compute single-digit sums for place-value clues (e.g., tens digit is 5+2; ones digit is 2+7). The Wrapping Up directs students to play the "Amusement Park Addition" game and instructs selecting the "sums to 100" option, offering some additional practice with addition facts.

Students solve time-based addition and subtraction problems in Activity 2 (for example, finding how long Karen, Greg, and Ally swam altogether = 50 minutes and how much longer Emmy swam than Scott = 15 minutes). In Activity 1 students match and order activities with time amounts (5, 15, 30, 60 minutes) and choose activities that correspond to 5- and 15-minute intervals, requiring comparison and use of minute quantities. The swimming problems ask students to add multiple lap times and subtract lap times to answer questions.

Students count by 5s and 10s to find coin totals and are repeatedly asked to add coin values (count dimes by 10s, nickels by 5s, pennies by 1s) to produce totals such as 44¢, 56¢, 63¢, 27¢, 53¢, and 70¢. Students show amounts using combinations of pennies, nickels, and dimes and practice exchanging coins (5 pennies = 1 nickel, 2 nickels = 1 dime) to make amounts with as few coins as possible. Activities require students to add multi-coin amounts aloud and write intermediate amounts (for example, counting 30 + 10 + 4 to get 44).

Students roll a die and add pennies to their collection, counting the pennies to find totals and exchanging 5 pennies for a nickel (Activity 1). The lesson asks and has students answer questions like "How much is two nickels worth?" and shows adding two nickels by counting by 10s. Students combine coins and state amounts (e.g., 1 quarter + 1 penny = 26¢; 1 quarter + 1 dime = 35¢) in Activities 2 and 4, requiring them to add small coin values.

Students repeatedly combine coin values when they play the money exchange game, collecting pennies and exchanging them for larger coins and bills. Students count the total value of coins they color on the "My Piggy Bank" page and write the amount in the blank. Students create money amounts from dice rolls (e.g., $3.64), write the amounts, and show them using bills and coins multiple times.

Students count and combine category totals when they answer questions such as "How many tables and chairs in all?" and "How many dressers and shelves in all?" on the Furniture Pictograph page. Students also solve comparison problems like "How many more chairs than beds?" and answer questions on the Favorite Sports page (e.g., "How many people like to watch tennis and soccer the most?" and "What's the difference between how many people like to watch swimming and how many like to watch soccer?"). The lesson's skills list explicitly states students will "solve simple put-together, take-apart, and compare problems" using graph data.

The lesson's Skills section explicitly states that students will "solve simple put-together, take-apart, and compare problems using information presented in a bar graph," which refers to addition and subtraction in context. In Activity 1 (Jelly Bean Tree) students place jellybeans on a bar graph and answer questions about the graph, providing practice counting and comparing quantities. Activity 3 and the Wrapping Up game ask students to read and interpret numeric scales (e.g., identifying values like 55 or numbers missing on a scale), which involves working with numerical amounts from graphs.

Students read the "Pets in Our Class" line plot and answer quantity questions, including "How many birds and fish do students in this class own? (5)", which requires combining two category counts (3 + 2). Students measure lines, write the lengths, place Xs on a measurement line plot, and count the Xs above each number to determine frequencies (answer key lists counts above 1–6). Students also play online "Interpret Line Plots" activities that ask questions about quantities on plots.

The lesson's Skills statement asks students to 'solve simple put-together, take-apart, and compare problems using information presented in a bar graph,' which directs students to combine or separate quantities. The Student Activity page gives specific counts for cupcake flavors (e.g., Vanilla 4, Chocolate 8, Lemon 2, Strawberry 5, Carrot 7, Apple 1) and prompts students to write questions for given answers such as 8, 12, 6, and 9, which requires students to form addition (or subtraction) questions using those one-digit counts. Activity directions and the Jelly Bean Tree game have students place and interpret counts on bar graphs, giving repeated opportunities to combine category counts.

The lesson's skills list explicitly states that students will "solve simple put-together, take-apart, and compare problems using information presented in a bar graph." Students collect data using tally marks, count items in four categories, and place numbers along the bar-graph vertical axis, including discussion of counting by 1s, 2s, or 5s. Step 9 asks students to answer comparative questions about most/least and what the data tells them, which can require combining or comparing category counts.