Grade: 3, Topic(s): addition/subtraction

## Purpose

To add 22 to any number using mental computation.

None

Say a number aloud, such as 8, and ask a student to add 22 to it. Continue choosing children to add 22 to the previous result.

If children have difficulty adding 22, you can remind them of the strategy for adding 12 (adding 10 and then adding 2 more) and encourage them to develop a similar strategy for adding 22. Children may find it helpful to add 20 and then 2 more, or to add 10 twice and then add 2 more. These strategies use children’s knowledge of place value (understanding that 22 means 2 tens and 2 ones).

Part 1 asks children to start at 0, which allows focus to be given to the strategy of adding 10, adding 10, and adding 2 more. In Part 2, children add 22 in a “chain” to a number greater than 3 but less than 10. The extension starts at a larger number.

Let’s start at 0 and add 22. Then we’ll add 22 again to *that *result and keep going until we reach at least 200.

- 0, 22, 44, 66, 88, 110, 132, 154, 176, 198, 220

*If children need more practice or are enjoying their mastery, repeat. If children are ready to move on, go to Part 2.*

Let’s start at 8 and add 22 to it. Then we’ll add 22 again to *that *result—and keep going until we reach at least 200.

- 8, 30, 52, 74, 96, 118, 140, 162, 184, 206

*If children need more practice, repeat. Or, when children seem excited for a new challenge, move to the extension.*

Let’s start at 27 and add 22 to it. Then we’ll add 22 again to *that *result – and keep going until we reach at least 300.

- 27, 49, 71, 93, 115, 137, 159, 181, 203, 225, 247, 269, 291, 313

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