Grade: 2, Topic(s): addition/subtraction, skip counting

## Purpose

To count forwards and backwards by tens across 200.

None

Choose a three-digit number that is not a multiple of 10, and have children count on by tens in unison past a new hundreds digit. For example, if you choose 127, the class would count 137, 147, 157… and would continue until passing 200. The children should stop once they pass into the next hundred. After repeating this with several other starting numbers, vary the activity by having children count backward by tens from a given three-digit number. For an extra challenge, say “Switch!” to change directions from counting forward by tens to counting backwards by tens.

Part 1, counting by tens, starts at a three-digit number between 100 and 200 that is a multiple of 10 (e.g., 130). Part 2 begins with a three-digit number greater than 200 that not a multiple of 10. The extension switches directions from counting forward by tens to counting backwards by tens from any three-digit number less than 300.

I’m going to say a three-digit number between 100 and 200 and we’ll count by tens starting at *that* number.

Examples:

- 123, 133, 143…193, 203, 213, 223
- 109, 119, 129…199, 209, 219, 229
- 156, 166, 176…196, 206, 216, 226

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

I’m going to say a three-digit number that is greater than 200 and we’ll count by tens starting at *that* number.

Examples:

- 205, 215, 225…295, 305, 315, 325
- 209, 219, 229…299, 309, 319, 329
- 256, 266, 276…296, 306, 316, 326

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

I’m going to say a three-digit number that is less than 200. We’ll start by counting forward by tens from *that* number. When I say “Switch!” we’ll change directions. (By choosing when to “switch” strategically, you can create more opportunities to practice adding and subtracting tens across 200.)

Examples:

- 187, 197, 207, 217,
*switch*, 207, 197,*switch*, 207, 217, 227, 237, 247,*switch*, 237,*switch*, 247, 257, 267 - 166, 176, 186, 196, 206,
*switch*, 196, 186,*switch*, 196, 206, 216, 226,*switch*, 216, 206,*switch*, 216, 226, 236

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