Lesson: Adding and Subtracting Numbers up to 20 Mathematics • 1st Grade

In this lesson, we will learn how to solve problems by deciding whether to add or subtract and then completing equations by adding and subtracting within 20.

Lesson Plan

Students will be able to

read, interpret, and model a word problem,
write an equation to represent a word problem,
choose whether addition or subtraction is needed to solve a word problem,
choose appropriate addition or subtraction strategies to solve word problems,
check if the answer to a word problem makes sense.

Lesson Worksheet

Q1:

James has a bag of 6 sweets and a bag of 9 sweets.

How many sweets does James have?

Q2:

A pirate found 16 jewels in a treasure chest. But 7 jewels were stolen.

Which picture shows this?

How many jewels were left?

Q3:

There were 11 flies. After a frog ate some of them, there were 8 flies left. How many flies were eaten?