Standard

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.

Student language:

• "I can use addition and subtraction to solve measurement problems."

Explanation

About the Math, Learning Targets, and Rigor

This standard applies the concept of length to solve addition and subtraction word problems with numbers within 100. Students need experience solving addition and subtraction word problems (use all types from Table 1) that use measures of length. It is important that word problems stay within the same unit of measure.

Students need to be able to use equations with a symbol for the unknown quantity (variable).

Example

A word problem for 5 – n = 2

Mary is making a dress. She has 5 yards of fabric. She uses some of the fabric and has 2 yards left. How many yards did Mary use?

Other equations include:

• 10 + 15 = c
• c - 20 = 5
• c – 10= 25
• 20 + b = 35
• 15 + a = 35
• 35 = a + 15
• 35 = 20 + b

Note: Help students develop and understanding of what the problem is asking. Sometimes “key words” can be misleading. The teaching of a “key word approach” limits the development of understanding what the problems is actually asking.

Resources

Videos

• Khan Academy
  • scroll to find 2.MD.5, click on a skill, watch videos on left side in each skill
• Learn Zillion

EngageNY Lessons

Extra Practice

• North Carolina Tasks
• Illustrative Math Tasks
• Howard County Tasks
  • Click on 2nd grade at bottom, then 2.MD.5
• Common Core Sheets

Released Assessment Questions

2.MD.5 Student Example

Back to 2nd grade homepage