# Lesson 4 More Addition and Subtraction with Tens

Let’s add and subtract tens.

## Warm-up Number Talk: Plus or Minus 10

Find the value of each expression mentally.

## Activity 1 How Many Are in the Bag?

Jada is counting collections of cubes.

In Bag A there are 30 cubes.

In Bag B there are 2 towers of 10.

How many cubes are in the two bags all together?

Show your thinking using drawings, numbers, or words.Tyler is counting a collection of cubes.

In Bag C there are 7 towers of 10.

He takes 40 cubes out of the bag.

How many cubes does he have left in the bag?

Show your thinking using drawings, numbers, or words.

## Activity 2 Add and Subtract Tens

Add 20:

Equation:

Subtract 20:

Equation:

4 tens and 5 tens is

Equation:

8 tens take away 3 tens is

Equation:

## Practice Problem

## Problem 1

Find the value of each expression.

Explain or show your reasoning.There are 7 towers of ten on the table.

Han takes 2 towers away.

How many connecting cubes are on the table now?

Explain or show your reasoning.