Missing addend worksheets with an answer key, made to order. Each problem gives the total and one of the numbers, and students find the other: 8 + □ = 13. Choose which number is missing, how large the numbers are, and whether some equations are written right to left.
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Missing numbers
Facts to 20
Fact strategies
Addition
Bigger addition
Subtraction
Across zeros
Mixed
Decimals
Missing addends within 20. Find the number that completes each sum.Two-digit missing addends. Two-digit sums with one addend hidden.Missing numbers, adding and subtracting. Any number can be the missing one, within 20.Missing digits. Find the hidden digits in each problem.Addition within 10. Sums up to 10, set in columns.Addition within 20. Sums up to 20, set in columns.Subtraction within 10. Starting numbers up to 10.Subtraction within 20. Starting numbers up to 20.Addition and subtraction within 20. Both operations on one sheet. Watch the signs.Adding three numbers. Three one-digit numbers across the line.Adding 9. Every problem adds 9, sums up to 20.Doubles. Doubles facts up to 10 + 10.Make 10. Find the number that makes 10.Two-digit plus one-digit addition. A two-digit number and a one-digit number.Two-digit addition, no regrouping. No column adds to ten or more.Two-digit addition. Two-digit numbers, regrouping as it comes.Two-digit addition with regrouping. Every problem regroups at least once.Two-digit addition, regrouping in every column. The ones and the tens both regroup.Three-digit plus two-digit addition. A three-digit and a two-digit number.Regrouping in the tens. Three-digit addition that regroups in the tens only.Three-digit addition with regrouping. Every problem regroups at least once.Four-digit addition with regrouping. Four-digit numbers, regrouping at least once.Column addition: four numbers. Four two-digit numbers in a column.Two-digit subtraction, no borrowing. Each top digit is the larger.Two-digit subtraction. Two-digit numbers, the larger on top.Three-digit subtraction, no zeros to cross. Each problem borrows; no zero in the way.Four-digit subtraction. Four-digit numbers, the larger on top.Subtracting across a zero. Three-digit numbers with a zero to work across.Subtracting across two zeros. Four-digit numbers like 5,002 − 1,348.Subtracting from round numbers. Starting from whole hundreds, like 600 − 89.Three-number subtraction. Take two numbers away, one after the other.Two-digit addition and subtraction. Both operations on one sheet. Watch the signs.Three-digit addition and subtraction. Three-digit numbers, both operations.Adding decimals: tenths. Tenths with up to two whole digits.Adding decimals: hundredths. Hundredths, the points lined up.Subtracting decimals: hundredths. Hundredths, the larger number on top.Adding and subtracting decimals. Tenths and hundredths together, both operations.Line up the decimal points. Copy each problem into the grid, then solve.
Make your own missing addend worksheet
Title and instructions
Left empty, the sheet is titled "Missing Addends".
A missing addend problem asks how two parts make a whole when one part is unknown. Students who can answer 8 + 5 often stall at 8 + □ = 13 because it reads as a question about subtraction: what is 13 take away 8? Seeing both forms side by side is what builds the link between addition and subtraction.
From Facts to Larger Numbers
Start within 10 or 20, then move to two-digit numbers, where finding the missing addend in 47 + □ = 82 needs regrouping. Make 10 fixes every total at 10 (7 + □ = 10), a strategy students lean on for facts like 8 + 5. The Missing digits sheets hide single digits inside a column problem instead, and each one has exactly one answer.
Checking the Answer
Every missing number can be checked by putting it back: if 8 + 5 = 13, the blank was right. Writing some equations right to left (13 = 8 + □) shows that the equals sign means "is the same as", not "the answer comes next".
For addition facts, column addition and timed tests, see the Addition Worksheets page.
