Using doubles to add worksheets

1. What does use doubles to add mean?

What does use doubles to add mean?

Double Facts are additions in which a number is added to itself. For example, 1 + 1, 2 + 2 etc. Internalizing double facts are helpful building blocks in developing fluency in adding single digit numbers. Double Facts within 20 Worksheet is about practicing double facts for numbers up to 10.