Adding Nine Worksheet

Students will fluently add 9 to a one-digit number within 20.

Students will apply the plus-nine fact to two-, three- and four-digit addends.

Students will recognize the plus-nine sum regardless of which addend is written first.

Because the four pages increase from single-digit to multi-digit numbers, they can be assigned to different students in the same class for differentiation rather than worked through in sequence by everyone.

The three Challenge problems on each page extend past that page's usual number range, making them useful as an extension for students who finish early.

Since both addend orders appear (for example 4 + 9 and 9 + 4), the set can double as practice for recognizing that order does not change the sum, not just for fact recall.

Plus-nine fact fluency — students solve equations from 4 + 9 through 9 + 9 to build automatic recall of the plus-nine addition facts within 20.

Commutative-property recognition — the worksheets use both addend orders, including 4 + 9 and 9 + 4, reinforcing that order does not change the sum.

Extension problem-solving — three "Challenge" problems per page push beyond that page's typical number range.