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1st grade math · Unit 1: Adding and subtracting within 20

Make a ten to add

What this lesson shows

8 + 5: move 2 into the ten frame, then 10 + 3 = 13.

The worked example

The lesson works this one step by step: 8 + 5 = □. Then your kid tries one like it on paper.

The steps

  1. Fill one ten frame
  2. Move some over to make 10
  3. 10 plus what is left

Helping at home

Ask how many more the bigger number needs to make 10. Take that many from the other number, then add what is left to 10. Draw two ten frames if it helps.

If your kid gets stuck

How many more to make 10?

Watch it with Lux

With Lux, this lesson is a narrated video and a printed page your kid works on. Then Lux helps with the same math on their own worksheet, one question at a time.

See how Lux works

Standards

  • Common Core 1.OA.C.6
    Add and subtract within 20, demonstrating fluency for addition and subtraction within 10. Use strategies such as counting on; making ten (e.g., 8 + 6 = 8 + 2 + 4 = 10 + 4 = 14); decomposing a number leading to a ten (e.g., 13 - 4 = 13 - 3 - 1 = 10 - 1 = 9); using the relationship between addition and subtraction (e.g., knowing that 8 + 4 = 12, one knows 12 - 8 = 4); and creating equivalent but easier or known sums (e.g., adding 6 + 7 by creating the known equivalent 6 + 6 + 1 = 12 + 1 = 13).
  • Common Core 2.OA.B.2
    Fluently add and subtract within 20 using mental strategies. By end of Grade 2, know from memory all sums of two one-digit numbers.
Matches a standard in all 50 states and DCSee each state's code

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