Take away tens

What this lesson shows

70 − 30 drawn as ten-sticks: 7 tens take away 3 tens leaves 4 tens, which is 40.

The worked example

The lesson works this one step by step: 70 − 30 = □. Then your kid tries one like it on paper.

The steps

1. Draw the tens
2. Cross out the tens taken
3. Count the tens left
4. Say it as a number

Helping at home

Say each number as tens: 70 is 7 tens. Draw that many ten-sticks, cross out the tens taken away, and count the sticks left. That many tens is the answer.

If your kid gets stuck

How many tens? How many go away?

Standards

• Common Core 1.NBT.C.6
  Subtract multiples of 10 in the range 10-90 from multiples of 10 in the range 10-90 (positive or zero differences), using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used.

More in this unit

• Adding ones to a two-digit number
• Get to the next ten
• Twelve ones is a new ten
• Count back to the ten
• Open a ten
• The ten you opened is gone