Lesson 5 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:


Practice Problem

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.