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

## Purpose

To build fluency with pairs of numbers that equal 10 and/or 100

10-dot display on index card or piece of paper

Using the 10-dot display pictured here, cover some of the dots with a blank index card (or paper). Ask children to determine how many dots they can see and how many are covered. Play for several rounds.

For an added challenge, change the value of each dot to be equal to 10. Repeat the game.

In Part 1, the value of each dot is equal to 1. In Part 2, the value of each dot is equal to 10.

(Show the 10-dot display to the children, and then cover some dots and show it to them again.) How many dots do you *see*? How many dots are* covered*?

Examples:

- 1 covered, 9 can be seen
- 5 covered, 5 can be seen
- 4 covered, 6 can be seen
- 3 covered, 7 can be seen

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

Now each dot is equal to 10. How many dots do you *see*? What is the value of the number of dots you *see*? How many dots are *covered*? What is the value of the number that is covered?

Examples:

- 1 covered (10), 9 can be seen (90)
- 5 covered (50), 5 can be seen (50)
- 4 covered (40), 6 can be seen (60)
- 3 covered (30), 7 can be seen (70)

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