Students read and solve vertical addition and subtraction problems (55 + 30, 74 − 50, 350 + 70, 420 − 40) and are prompted to explain place value for each digit. Students are allowed to use base-10 blocks or an abacus and are guided to add/subtract the ones place first and use carrying or borrowing as needed. Student pages explicitly teach addition strategies (commutative property, doubles, making tens, fact families, adding nines/eights) and subtraction strategies (neighbors, half facts, counting back/counting up), and a "Working With Big Numbers" page gives step-by-step borrowing and composing-10 procedures for multi-digit problems (e.g., 342 − 167, 198 + 117).

The Basic Skills Review includes three-digit addition and subtraction problems such as 287 + 464 = 751 and 893 - 278 = 615, requiring students to work within 1000. The text asks students to recall addition strategies (doubles, making 10, adding multiples of 10, carrying, and regrouping) and to review "Math Strategies Review" sheets in their Interactive Notebook. The activities and game reminders prompt students to use addition facts while working on related tasks.

Students complete Basic Skills Review items that require adding 592 + 368 and subtracting 872 - 465, giving direct practice with three-digit addition and subtraction within 1000. Students create repeated addition sentences (e.g., 6+6, 3+3+3+3+3+3+3) and use number lines and skip counting to compute products, which involves repeated use of addition operations. Activity 4 asks students to write repeated addition representations (e.g., 3+3+3+3) when modeling multiplication sentences.

Students use the abacus to model and compute sums such as 10+40 and 22+9, including trading beads to make tens and counting by 2s, 5s, and 10s. Students complete vertical addition and subtraction examples (378+500 and 515-400) on the Basic Skills Review and practice counting back by tens from 645. Students check sums on the abacus when verifying domino-generated problems, reinforcing place-value reasoning for some addition tasks.

Students are asked to find what number is 10 more, 10 less, 100 more, and 100 less than a given three-digit number in the introductory questions. Students complete a "Skip Counting Within 1000" sheet and practice counting by 10s and 100s (e.g., counting by 10 to order index cards and counting by 100 from 290 to 990). These activities require students to manipulate numbers within 1000 using place-value increments.

Students practice rounding whole numbers to the nearest ten and hundred in the introductory exercises and use rounding to check sums (e.g., rounding 654+207 to 650+210 and comparing 861 to the estimate 860). Activity 1 has students match exact addition and subtraction sentences with their rounded forms and produce estimated answers for problems such as 76+22, 125+649, 684-76, 356-217, and 815+165. Activity 2 directs students to practice estimating sums up to 1000 and notes that students may need to compose tens and regroup/carry when finding some exact sums.

The Skills and Activities explicitly teach place-value strategies and algorithms: students model numbers with base-10 cards and the abacus (Activity 1 and 2), write numbers in expanded form, line up digits and add vertically (Student Activity Page Step 2), and practice regrouping on paper with a worked example (1879+4327) in Activity 3. The Wrapping Up section has students find differences for problems such as 60-30 and 856-20 and use addition to check subtraction, demonstrating use of the relationship between addition and subtraction.

Students solve and estimate addition problems that are within 1,000 (368+212, 435+120) and subtraction problems within 1,000 (784-231, 689-357). Students are asked to explain steps for multi-digit addition and subtraction, showing regrouping/carry and borrowing (e.g., adding 4652+4678 and subtracting 5683-3900) and to use rounding and estimation to check answers. The activity asks students to describe addition as putting numbers together and subtraction as taking them apart, and to use place-value representations (place value cards, expanded form) when working with numbers.

Students count and combine 1-cup or 1-pint measures to determine the total capacity of containers (Activity 1, Activity 4) and record totals on the How Much Will It Hold? sheet. Students answer comparative questions that require finding differences (e.g., "How much more water does the largest container hold than the next largest container?"), and they keep tally marks or write counts as they add successive cups. Students also add repeated measures when converting between units (e.g., determining that 1 gallon = 16 cups, 1 pint = 2 cups).

Students interpret scale readings and compute new weights by adding or subtracting given amounts in the "Reading Scales" problems (for example, +9 lb, +10 oz, -7 lb). Students add and subtract item weights in "Packing My Lunch" to find totals and differences in ounces (e.g., computing 17 oz, 15 oz, and a 12 oz difference). Students deduce individual shape weights by solving addition problems in "What Do They Weigh?" and are prompted to write addition and subtraction sentences on scratch paper.

Students solve one-step addition and subtraction problems with time (e.g., finding what time it will be in 5, 20, 30, or 45 minutes; finding times an hour earlier or later; computing elapsed time like 4:15 to 6:45). The skills list explicitly states that students will "Add, subtract, multiply, or divide to solve one-step word problems involving weights or volumes given in the same units." The unit test includes weight addition questions (e.g., a block weighs 8 oz, what is 10 oz more; what do 3 identical blocks weigh altogether).

Students are instructed to "use what you know about addition, subtraction, multiplication, and division to fill in the blanks" while calculating packages and supplies for 60 people. The text explicitly suggests breaking larger numbers into smaller numbers and gives the distributive property of multiplication as an example strategy. Students compute counts and leftovers for items on the Picnic Food and Picnic Games pages, which requires performing addition, subtraction, multiplication, and division to find totals and remainders.

Students are asked to compute totals of sides and vertices and to write number sentences (e.g., "How many vertices do 4 squares and 3 hexagons have? Write a number sentence to show your answer." with the answer key showing 16+18=34). The answer key and problems include multi-digit addition examples such as 12+35=47, 8 rectangles → 32 sides, and 6 triangles → 18 vertices, which require students to add groups of numbers.

Students measure and label side lengths and then add those lengths to find perimeters (for example, labeling sides and computing 6+4+6+4 = 20 and finding a perimeter of 22 for a 3-by-8 rectangle). The student activity page and answer key explicitly state that "We use addition to find the perimeter of polygons," and multiple hands-on tasks have students count tiles and add side lengths to compute perimeters. The lesson also introduces multiplication as a shortcut for regular polygons, reinforcing repeated-addition structure.

Students compute perimeters by adding side lengths in numerous problems (e.g., examples showing 3+5+3+5=16 cm, 12+2+12+2=28 cm, and 8+10+12=30 m). The materials instruct students to use repeated addition or multiplication for regular polygons (e.g., 4×6=24 in., and advice to add a side four times for a 13-unit square). Activity tasks require students to write number sentences for perimeters (e.g., 2+6+2+6=16, 2+2+3+3+4+4=18), and Basic Skills Review includes subtraction and addition computations (e.g., 32-10=22 and 3948+1277=5225).

Students add side lengths to find perimeters by counting tile edges and labeling side lengths on shapes (Activity 1 and pentomino activities). Students use addition to compute total perimeter (e.g., filling in perimeters for pentomino shapes and irregular shapes) and use subtraction to find missing side lengths when given a total perimeter (e.g., triangle with sides 3, 4, n and perimeter 12; rectangle with perimeter 18 and one side 4). Students repeatedly practice finding perimeters and missing lengths using the relationship between addition and subtraction across multiple activities and worksheets.

Students compute perimeters by adding equal side lengths (e.g., matching a regular pentagon with sides 8 ft to perimeter 40 ft, a regular octagon with sides 8 in to 64 in, and squares with side lengths 7 in → 28 in and 9 ft → 36 ft). Students use colored unit tiles to build shapes and count side units to find perimeter totals on the "Practicing Perimeter" page, and they model arrangements with tiles that require combining counts (e.g., seating arrangements and counting how many people are seated). The Basic Skills Review includes arithmetic problems where students compute totals and differences (for example, Carlota's 7×6 = 42 and 42 − 12 = 30).

Students add side lengths to calculate perimeters (e.g., 2+2+4+4=12 in., 4+4+6+6=20 in., 2+2+6+6=16 in.). Students count and combine unit tiles to find areas (filling a 6 by 4 box to get 24 tiles, finding 12 and 8 square inches for other boxes, and making shapes with 15 tiles). The Basic Skills Review includes a subtraction step (56 - 8 = 48) and other arithmetic problems that require computation.

Students decompose composite figures into rectangles and squares and then add the areas of each part to find total area (e.g., 16 sq. cm + 36 sq. cm = 52 sq. cm in Activity 2). Students create and combine cut-out shapes to make target total areas (e.g., making 43 sq. cm and 100 sq. cm by adding areas of 2–3 shapes) and count and label squares in garden designs, then add the two section areas to find totals (Activity 3). The Basic Skills Review includes arithmetic tasks in which students compute differences and totals (for example 72 − 40 = 32 and other addition/subtraction problems).

Students count square units to find areas of letters and creature body parts and record area and perimeter on the grid (Activity 1 and Activity 3). Students decompose rectilinear figures into non-overlapping rectangles and add the areas of the parts (Skills list and Getting to Know My Creature total area calculation). The activities ask students to find total area and total perimeter by combining the areas/perimeters of individual parts and to use a whiteboard for computation.

The Basic Skills Review #20 includes arithmetic tasks in which students compute 8 × 10 = 80 and then subtract 12 to find 80 − 12 = 68, requiring subtraction within 1000. Students then use that result in a division task (68 ÷ 7) and solve other number problems on the same sheet. The sheet also contains a subtraction problem 4444 − 1199, and students are given scratch paper to use as needed for computations.

The lesson asks students to "Solve one- and two-step 'how many more' and 'how many less' problems using information presented in graphs" and includes specific problems requiring numerical comparison (for example: "How many more chocolate bars and gummy bears combined sold than popcorn? (2)"). Students create and interpret pictographs and bar graphs with numeric scales (including a pictograph where one picture = 10 and bar graphs with y-scales up to 100) and complete activities that require reading numeric values from graphs and comparing totals.

Students solve one- and two-step "how many more" and "how many less" problems using information presented in graphs (listed in Skills). Students read scaled pictographs and compute values from a scale (e.g., one book icon = 10, Tuesday = 60, Friday = 100) and determine combined counts for days (e.g., which two days total Friday). Students use numeric relationships to fill a chart (e.g., given mystery = 25, compute fiction = mystery + 15, autobiography = mystery - 10) and then translate counts into pictograph units (each shaded square = 5 books).

The Basic Skills Review #24 asks students to compute 7 × 8 = 56 and then subtract 15 to find 56 − 15 = 41, an explicit subtraction within 1000. The review also includes other arithmetic items (e.g., 8642 − 5678) that show subtraction problems are part of the practice set. Students are given scratch paper to use as needed for these computations.

Students compute totals and values for coin groups in Activity 2 (e.g., finding that pennies, nickels, dimes, quarters, and half-dollars total $4.30) and write those amounts in a table. In Activity 1 students are prompted to find sums and differences from their pictograph data. The Basic Skills Review #25 asks students to perform subtraction within 100 (90 − 17 = 73) and other arithmetic problems.

Students are asked to compute totals and differences from graphs (e.g., "How many boxes were sold on Tuesday and Thursday combined? (7)" and "How many more boxes were sold on Friday than on Saturday? (7)"). Students add monthly values from a bar/line graph (e.g., "How many miles did he hike in July and August combined? (130)"). The Unit 8 Test asks students to compare and combine quantities from a pictograph (e.g., "How many more books did he read in August and September combined than in April? (15)").

Students are asked to "figure out and write down the totals for the cupcake flavors sold in a week, the number of visitors for each day of the week, and the numbers of cupcakes bought by individual customers," which requires adding counts. The lesson directs students to total tally-chart data and calendar visitor numbers and suggests checking these totals ("can check them using a calculator"). Students also decide on scales (e.g., a scale of 5 or 2) which involves grouping values when preparing graphs.