# 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?

1. 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.

2. 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

1. Add 20:

Equation:

2. Subtract 20:

Equation:

3. 4 tens and 5 tens is

Equation:

4. 8 tens take away 3 tens is

Equation:

## Problem 1

1. Find the value of each expression.
Explain or show your reasoning.

2. 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.