Students solve a length word problem about a birdhouse: "She started with a height of 6 inches... increased the height by 2 inches," and the answer key shows 6 + 2 = 8, 8 inches. The Making Addition Problems materials include an "inches" item with a ruler graphic, and students are asked to create addition problems that could use inches. Students are asked to use drawings, tally marks, counters, or an abacus as strategies and to work with missing-addend equations (e.g., 2 + ___ = 5 and the beanbag toss missing-addend activity).

Students practice addition and subtraction within 100 on timed "Fact Power" worksheets (Fact Power 3 and 4) that present many single- and double-digit problems. Students are required to create a Mathematical Ocean Adventure story that includes two addition problems and two subtraction problems and to show their addition and subtraction in mathematical language (for example, writing 8+4). Students record answers on an answer page, reinforcing solving arithmetic problems embedded in story contexts.

Students physically measure objects in inches using a ruler and record measurements (Activity 1 and Activity 2). Students combine straw pieces to make a total length (e.g., put 3- and 6-inch pieces together or 4- and 5-inch pieces to show 9 inches), and students answer questions about adding or removing an inch from a drawn 5-inch line. Students identify half-inch marks and measure lines of 5 1/2 and 3 1/2 inches, showing understanding of lengths in the same unit.

Students use a ruler to draw lines of a given number of inches when they roll a die and create line art, which has them measure and produce lengths in the same unit. Students build shapes on a geoboard with side lengths given in centimeters (e.g., squares with 9 cm and 15 cm sides, a rectangle with 6 cm and 12 cm sides) and answer a question about the length of a missing side (triangle with two 18 cm sides; third side given as 25 cm). Students practice addition and subtraction within 100 by solving vertical number sentences such as 89-17 and 29+55.

The lesson's Skills list explicitly includes: "Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units." In Activity 2 (Comparing Ribbons) students measure ribbon pieces in inches, estimate lengths, measure two pieces, and write subtraction sentences such as "9 in. - 7 in. = 2 in." to find differences. The Kitchen Measurement activity asks students to identify the longest and shortest objects, calculate the difference in length between them, and "write a subtraction sentence and calculate the difference," using the same units for comparison.

Students measure seven gummy worms in centimeters before and after stretching and record those lengths on the Gummy Worm Stretching sheet. They are directed to find the difference for each worm and are explicitly asked, "Do we add or subtract to find differences? (subtract)," with guidance to begin the subtraction sentence with the larger number and use tools (whiteboard, abacus, counters) to compute. Students also measure lines in inches with a ruler and place Xs on a line plot, using rulers/number lines as drawn measurement representations.

The Skills list explicitly states that students will "Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units." Activity 2 directs students to complete Measurement Problems by writing number sentences and finding sums or differences, allowing them to draw pictures and use counters or an abacus; the provided answer key shows addition and subtraction equations (e.g., 3+6, 11-5, 29-26) all involving lengths in the same units and within 100. Activity 3 has students measure objects with a ruler and meter stick, reinforcing measurement in consistent units before solving problems.

Students use a labeled map with distances in miles and solve route questions that ask for totals or differences (e.g., "How many miles is it from Additionville to Measurement Bay if you drive through Fort Fact Power?"). Students are prompted to determine whether to add or subtract, write a number sentence, and find the sum or difference, and manipulatives or the map can be used as a visual aid. The provided answer key shows students computing multi-step sums and differences (for example 184+100+174 = 458 and 188+147+174 = 509).

Students cut out activity boxes labeled with times (1 hour, 30 minutes, 15 minutes) and place them into hourly schedule blocks. They are asked to pair two 30-minute activities to make an hour and to combine 15-minute activities to make a half hour. Students are prompted to check each hour block and answer "Are you sure that the activities in each one add up to an hour? Can you prove this?"