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

Doubles and near doubles

What this lesson shows

6 + 6 = 12, so 6 + 7 is one more: 13.

The worked example

The lesson works this one step by step: 6 + 7 = □. Then your kid tries one like it on paper.

The steps

  1. Find the double
  2. Add 1 more
  3. That is the sum

Helping at home

Look for a double. When the two numbers are one apart, add the smaller one twice, then 1 more. Two rows of cubes show it.

If your kid gets stuck

Is there a double close by?

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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