Dimes, Dimes, Dimes
Students will be able to subtract multiples of 10.
Introduction (5 minutes)
- Ask students how much a dime is worth.
- If you have a dime (real or plastic) show it to the class.
Explicit Instruction/Teacher Modeling (10 minutes)
- Ask students how much money you would have if you had five dimes.
- Draw five circles on the board. Write “10” in each circle. Show students how to count to 50 by tens.
- Now ask students how much money you would have if you had 10 dimes.
- Draw five more circles on the board and count to 100.
Guided Practice/Interactive Modeling (10 minutes)
- Tell students that you want to buy something that costs 30 cents. Ask how many cents you would have left if you start with 100 cents and spend 30 cents.
- Have students turn to a partner to share their answer.
- Now write 100 - 30 = 70 on the board.
- Tell students that you’d like to buy either an apple for 40 cents or a pear for 30 cents.
- Ask, “Could I buy both the apple and the pear?”
- Have students work with their partner to figure out whether or not this would be possible.
- Write on the board 70 - 40 - 30 = 0.
Independent Working Time (15 minutes)
- Pass out paper to each student. Tell them to draw a store where everything can be paid for in dimes. The prices of the items in the store should be 10 to 100 cents.
- After students draw their stores, they should work with a partner to “purchase” items from the store.
- Each student will start with 100 cents. As students purchase items, they should write number sentences showing how they subtracted the money they spent from 100.
Enrichment: Have students start with 200 cents when shopping in their partner’s store.
Support: Have students work with manipulatives (plastic coins) or real dimes.
Assessment (5 minutes)
- Assess students’ understanding by observing how they are subtracting by ten.
- Are they able to mentally subtract? Pay attention to the number sentences they write.
Review and Closing (5 minutes)
- Have students share the shopping they did at their partners’ stores and the number sentences they wrote.