Students divide concrete objects (12 pretzels) into equal groups and record outcomes such as 2 groups of 6, 3 groups of 4, 4 groups of 3, and 6 groups of 2 (Activity 1). Students use counters to create two rows to decide which numbers 1–20 can be divided into equal groups, supporting array-like thinking for two-row arrangements (Activity 3). The Skills section asks students to "write an equation to express an even number as a sum of two equal addends," which requires students to express equal grouping as an addition equation for two addends.

The Skills section tells students to determine whether a group (up to 20) is odd or even by pairing or counting by 2s and to write an equation to express an even number as a sum of two equal addends. The Photo Journal requirements ask students to include images of "Equal groups of objects" (example: two toy figures and a plate of 6 cookies split into two equal groups). Students are directed to label photos using correct mathematical language and to write short captions such as "An odd number of eggs" or examples showing equal groupings.

Students identify rows and columns in real objects (muffin tin, egg carton) and name arrays (e.g., 4 by 3, 2 by 6). Students write repeated-addition number sentences for arrays (Activity 2 shows 6 + 6 = 12 and 3 + 3 + 3 + 3 = 12; the Arrays and Addition page and Interactive Notebook require writing number sentences). Students create arrays with counters, dice, and worksheets and then write the corresponding addition sentences (Day 2 dice activity, Day 3 Arrayville prompts asking "What number sentences do your buildings show?").

Students are shown a 3 x 3 array and asked to explain how arrays relate to addition, then write the repeated-addition sentence 3 + 3 + 3 = 9. Students are prompted to create a "number collection" for 15 and given the 3 x 5 array as an example of a representation that uses addition. The Skills list explicitly states using addition to find totals of rectangular arrays up to 5 by 5 and writing equations as sums of equal addends.

Students generate and record all addition sentences that total 5 using 2, 3, 4, and 5 addends in the "How Many Ways" activity, including repeated-addend examples such as 1+1+1+1+1. Students practice adding multiple items in the ticket problems by totaling costs of combinations (e.g., game + ride, food + drink) and write equations for those totals. Students practice repeated addition and fluency with sums up to 20 in the Fact Power drills and the Brain vs. Calculator activity.

Students are explicitly asked to include an 'array' in their Mathematical Ocean Adventure (the Requirements sheet lists 'An array' and the Evaluation rubric scores '1 array'). Day 2 and Day 3 direct students to include math in their words and pictures and to add answers for problems on the answer page, which prompts students to represent mathematical ideas within their story pages. The planning sheet asks students to brainstorm 'Ways to use math,' providing space for students to plan where an array might appear.

Students use geoboards and rubber bands to create squares and rectangles, including tasks to make a square made up of 2 rectangles, a rectangle made up of 2 or 3 squares, and a rectangle made up of 3 rectangles. Students count how many squares they can make on the geoboard and record findings with tally marks, and the activity asks them to find rectangles of varying sizes. The lesson asks students to create nested squares of different sizes and to identify and name shapes based on their side and angle attributes.

Students create rectangles on a geoboard and count how many equal squares make up the rectangle (e.g., find 6 squares, create a 12-square rectangle, and create a 3x5 grid of 15 squares). Students divide those rectangles into equal shares (halves, thirds, fourths) and determine how many squares are in each part (for example, 12 squares divided into halves gives 6 in each half; 12 into thirds gives 4 in each third). The activities require students to work with rectangular arrangements of unit squares and reason about equal groups within those arrays.

Students glue coins into clear rows (for example, 1 row each of quarters and dimes, 2 rows of nickels) and count dimes by 10s and nickels by 5s to show they total 100 cents. Students arrange coins on activity pages that show grids and columns for nickels, dimes, and quarters and match pictures of coin collections to dollar amounts. Students are asked to show a dollar in several different ways using grouped coins.