Strategies for Learning Addition Combinations to 10 + 10:

Students will have Addition Fact Cards for practicing these combinations.

•

The Doubles—

from 3 + 3 to 10 + 10. Students learn most of the

doubles readily and can use the doubles they know to help with the

harder doubles. “I know that 6 + 6 is 12, so 7 + 7 is 2 more, that’s 14.”

•

The Near Doubles—

3 + 4, 4 + 5, 5 + 6, 6 + 7, 7 + 8, 8 + 9, and 9 + 10. These are one

more than the doubles. Students can use the doubles they know to learn these. “I know

5 + 5 is 10, so 5 + 6 is 1 more which is 11.”

•

Sums that Make 10—

1 + 9, 2 + 8, 3 + 7, 4 + 6, 5 + 5, 6 + 4, 7 + 3, 8 + 2, and 9 + 1.

Students need many experiences building all the ways there are to make 10 with

manipulatives until they recognize these combinations.

•

The 10+ Combinations –

from 10 + 3 to 10+10. Because these combinations follow a

structural pattern, students learn them readily once they have built them repeatedly

with cubes or counted them out on the 100 chart.

•

The 9+ Combinations –

from 9 + 3 to 9 + 10. Students can think of these

combinations this way: To solve 9 + 6, take one from the 6 and add it to the 9 to make

10. The 5 that is left is added to the 10, 10 + 5 = 15. Or, if we used 10 + 6 the answer

would be 16, but because we added 1 extra when we take it away we get the answer

15.

Addition Fact Cards:

Students work on addition combinations they are trying to learn

better. They write a clue or strategy for each one. If the student does not have the

combinations for 10 at recall there are games that can be requested that will help this

practice.

Examples:

4 + 3 =

3 + 4 =

Clue

: I know 3 + 3 = 6, so 4 + 3 is one more

which is 7.

3 + 5 =

Clue

: I know 5 + 5 = 10. Three is 2 less than

5 so 10 – 2 = 8

3 + 6 =

Clue

: I know 6 + 4 = 10. Three is one less

than 4 so, 6 + 3 =9

3 + 8 =

Clue

: I know that 8 needs 2 more to make 10

so I make the 3 into a 1, 10 + 1 = 11

3 + 7 =

Clue

: I know my 10 combinations

3 + 9 =

Clue

: I take one from the 3 and make 9 into a

10. 10 + 2 = 12

Third Grade Computation Expectations:

Fluent with number combinations to 10 + 10;

strategies for combinations to 100.