Adding ones to a two-digit number

What this lesson shows

36 + 5 in blocks: 11 ones make a new ten and 1 one. 41.

The worked example

The lesson works this one step by step: 36 + 5 = □. Then your kid tries one like it on paper.

The steps

1. Tens and ones
2. Add the ones
3. Ten ones make a new ten

Helping at home

Show the number as tens and ones, then add the ones. When there are 10 ones or more, trade 10 of them for a ten.

If your kid gets stuck

Are there 10 ones to trade?

Standards

• Common Core 1.NBT.C.4
  Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, 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. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.

More in this unit

• 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
• Take away tens