Addition and subtraction within 20 worksheets

Mixed addition and subtraction asks children to do one important thing before calculating: notice the operation sign. These printable worksheets interleave both skills within 20 after each one has been practiced on its own.

Kid stuck on one? You don’t just get the sheet.

Addition and subtraction within 20
Addition and subtraction within 20 worksheet — Mixed signs to 20, free printable with answer key

The answer key prints on a separate page.

What's on this sheet

A child can complete a page of addition correctly and still miss mixed questions by carrying the previous operation into the next line. Interleaving plus and minus signs builds the habit of reading each equation before solving it, a small decision that matters throughout later mathematics.

Why this sheet works

This ready-made sheet keeps every number within 20 and avoids carrying or borrowing, so attention can stay on choosing the operation. These sheets draw from both operations and never repeat a question on the same page, making the set varied without becoming unpredictable.

How this one works

One question from this sheet, worked through a step at a time.

11 + 3

11=10+1
1+3=4
10+4=14
  1. 11 + 3. Only the ones change — 11 is 10 and 1, and the 3 goes onto the 1.
  2. 1 + 3 = 4, and the 10 has not moved: 11 + 3 = 14.