Addition within 20: printable worksheets

Adding within 20 is where first graders move from counting objects to knowing number facts. The goal is not speed for its own sake. Children who can break numbers apart, count on from the larger addend, double a number, or make a ten before adding the rest are building habits that carry them through every later year of arithmetic.

This worksheet mixes the kinds of problems a first grade classroom uses. You can ask for plain addition facts, problems with a missing addend, problems with three addends, and true or false equations that ask a child to decide whether both sides are equal. For the youngest learners there is a picture version, where the child counts the groups shown and writes the sum. Sums can be capped low for confidence or opened up all the way to twenty, and problems can be written across the page, stacked in a column, or both.

What to watch for

Two mistakes are very common. Some children count the starting number again when they count on, so they land one too high. Others read the equal sign as a signal that the answer comes next, so an equation written backward looks wrong to them. The missing addend and true or false settings are there to bring these ideas out.

• Start with sums up to ten and pictures if your child still counts every object.
• Turn on make a ten once sums go past ten, so eight plus five becomes ten plus three.
• Add doubles and near doubles to give a quick way to remember many facts.

The button above opens this exact sample in the builder, where you can adjust the settings and print a new sheet and answer key.