The purpose of this activity is for students to learn Stage 5 of the Target Numbers center. Students subtract two-digit numbers to get as close to 0 as possible. For the introduction of this stage, invite students to count by 10 to 100 and represent their count with base-ten blocks. Then they take turns rolling the number cubes to get a number to subtract. They choose one of the numbers on the cubes to represent the tens and a different number to represent the ones. Students subtract their tens and ones from the starting number. The difference becomes the first number in the next equation. The player who gets closest to 0 in 4 rounds, without going below 0, is the winner.

• Display equation:
• Draw or display number cubes showing 4, 2, and 5.
• “What two-digit numbers could you create with this roll that would make you need to decompose a ten to subtract? How do you know?” (24, because if you subtract by place, there are only 3 ones, so you would need to decompose to take away 4 ones.)
• “What two-digit numbers could you create that wouldn’t require decomposing a ten? How do you know?” (52, because if you subtract by place there are 3 ones and you can take away 2 ones from 3 ones.)
• “What number would you create to try to get to get closer to 0 the fastest? Explain. (54, because it’s the number that lets you take away the most tens and ones.)

The purpose of this activity is for students to choose an activity to work on that focuses on addition and subtraction within 100 or on building fluency with addition and subtraction within 20. Students choose from previously introduced stages of the listed centers. Stage 4 of Capture Squares is also included to provide students an opportunity to practice subtraction within 20.

• Target Numbers
• Capture Squares
• Five in a Row

• “Which activity did you choose? What did you like about the activity you chose?”