Students will learn how to use addition and subtraction within 100 to solve word problems involving lengths in inches or feet. No problem will involve both a measurement in inches, and a measurement in feet.

Length word problem example (US Customary) by Khan Academy

Next, students will learn how to use addition and subtraction within 100 to solve word problems involving lengths in centimeters and meters. No problem will involve both a measurement in centimeters, and a measurement in meters.

Length word problems by Khan Academy

Length word problems by Khan Academy

Next, give your students this challenge:

2019 Math Kangaroo Levels 1-2 Problem #18 by STEM4all

Conclude by leading this investigation:

Bubbling Cauldrons (single digit addition)

by MathPickle

2.MD.B.5: Use addition and subtraction within 100 to solve word problems involving lengths that are given in the same units, e.g., by using drawings (such as drawings of rulers) and equations with a symbol for the unknown number to represent the problem.