Adding Doubles Minus 1 Worksheets for 1st Grade
Add two numbers that are exactly 1 apart, counting down from a doubles fact. 15 free printable worksheets, each with an answer key.
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Click a worksheet to open the PDF, or grab the matching answer key. Every sheet prints on one page.
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Adding Doubles Minus 1: what children learn
"Doubles minus 1" facts (like 6 + 5) can be solved by rounding up to a doubles fact and backing off by one — 6 + 5 is double-6 (12) minus one, the same shortcut as doubles-plus-1 approached from the other direction.
Adding Doubles Minus 1: worked example
6 + 5 = 11
6 + 5 is one less than the doubles fact 6 + 6 = 12, so 6 + 5 = 12 - 1 = 11.
Adding Doubles Minus 1: a common mistake to watch for
Kids sometimes round to the wrong double (using 5 + 5 instead of 6 + 6) — reminding them to double the BIGGER of the two numbers keeps the shortcut consistent.
Adding Doubles Minus 1: how to help at home or in class
Draw two numbers that are one apart, such as six and seven, and ask your child whether it is easier to double the smaller or the larger one. Then remove a single counter to land on the sum. Place two groups of counters on a table, pretend to borrow one from the bigger group, and note that the total does not change if you give it back. When your child can decide which double to use, mix all three double-based strategies.
What is on these Adding Doubles Minus 1 worksheets
This set has 15 different worksheets for 1st grade, with 8 questions on each and a matching answer key for every sheet. The instruction printed on each worksheet is: “Add the numbers and write the sum.”
Example questions like the ones on these worksheets, with their answers:
- 7 + 6 =13
- 4 + 5 =9
- 3 + 2 =5
- 1 + 2 =3
- 7 + 8 =15
- 9 + 10 =19
- 9 + 8 =17
- 4 + 3 =7
Every answer on every sheet is checked by a separate program before the worksheet is published. How we check answers