 Addition to 20 with one more or one less

# Addition to 20 with one more or one less

Start a free trial. 8,000 schools use Gynzy 92,000 teachers use Gynzy 1,600,000 students use Gynzy

## General

Students learn to add to 20 in problems where they either add one more or take one away to find their total.

-1.OA.C

## Introduction

Make a number snake with the students in the classroom. Start the snake at number 10, and have them count on by ones until they reach 20. You can repeat this a few times with different heads for the snake. Next, students must indicate what the neighbor numbers of the given numbers are.

## Instruction

Check that students understand adding to 20 with one more or one less by asking the following questions/giving the following questions:
- What do you need to look at to decide if you add with one more or one less?
- Calculate the following: 10+7= and 10+8=
- Calculate the following: 4+8= and 4+7=

## Quiz

Students first practice calculating addition with one more or one less by selecting a multiple choice answer. Then they must give their own answer to an addition problem with one more or one less. Finally, they must practice addition with one more or one less as well as making tens to solve for their answer.

## Closing

Show the table on the interactive whiteboard. Explain how to read the table and then ask students to complete the table.

## Teaching tips

Students who have difficulty with adding with one more or one less can make use of MAB blocks or other manipulatives. Have them set out blocks to represent the addition problem. Then ask them to demonstrate a problem with one more or with one less by moving one block to one of the groups or by taking one away.

## Instruction materials

Optional: blocks or manipulatives

### The online teaching platform for interactive whiteboards and displays in schools

• Save time building lessons

• Manage the classroom more efficiently

• Increase student engagement 