# Section A: Practice Problems Units of Ten

## Section Summary

Details

We learned how to show tens in different ways.

6 tens

60

We learned how to add and subtract tens from other tens.

4 tens and 1 ten is 5 tens

5 tens take away 2 tens is 3 tens

## Problem 1 (Pre-Unit)

1. Mai says the numbers 10, 20, 30.
What is Mai counting by?

2. What is the next number Mai will say?

## Problem 2 (Pre-Unit)

How many are in each picture?

## Problem 3 (Pre-Unit)

Which expression shows the number of dots?

## Problem 4 (Pre-Unit)

Find the number that makes each equation true.

## Problem 5 (Lesson 2)

How many connecting cubes are in each picture?

## Problem 6 (Lesson 3)

1. How many connecting cubes are in the picture?

2. Circle the picture that shows 10 more connecting cubes. Cross out the picture that shows 10 fewer connecting cubes.

## Problem 7 (Lesson 4)

1. Find the value of each expression.

2. There are 7 towers of ten on the table.
Han takes 2 towers away.
How many connecting cubes are on the table now?

## Problem 8 (Exploration)

You can use towers of 10 cubes to help you with these questions.

1. Noah has 70 cubes in towers of 10.
He gave some towers of 10 to Clare.
Then he gave some towers of 10 to Andre.
Now Noah has no cubes left.
What is one way Noah could have done this?
Show your thinking using drawings, numbers, or words.
Write equations to represent the problem.

2. What is another way Noah could have done this?
Show your thinking using drawings, numbers, or words.
Write equations to represent the problem.

3. Diego has 10 cubes in a tower.
Elena gave him some more towers of 10.
Then Mai gave him some more towers of 10.
Now Diego has 60 cubes in towers of 10.
What is one way this could have happened?
Show your thinking using drawings, numbers, or words.
Write equations to represent the problem.

4. What is another way this could have happened?
Show your thinking using drawings, numbers, or words.
Write equations to represent the problem.