Numerous Names for Numbers
Students will be able to solve problems using different combinations of tens and ones to represent 2-digit numbers.
- Ask your students to give you different ways to show the number 25.
- Write the number 25 on the board.
- Have students say the number.
- Then, have volunteers demonstrate the number using connecting cubes.
- Tell students that today they are going to learn different names for numbers.
Explicit Instruction/Teacher modeling(10 minutes)
- Use connecting cubes or base ten blocks to show the number 34 using 3 tens.
- Ask your students to determine how many ones are needed.
- Trade 1 tens block for 10 ones blocks. Ask your students to identify how many tens and ones you have now.
- Trade another tens block for 10 more ones blocks, asking your students again to determine how many tens and ones blocks there are.
- Record all answers on the board.
- Discuss the pattern with students.
- Remind students that when exchanging tens and ones in a number, the value of the number doesn't change.
Guided Practice(10 minutes)
- Write a problem on the board. For example: Dan wants to buy 21 stickers. He can buy stickers in packs of 10 or as single stickers. What are the different ways Dan can buy 21 stickers?
- Read aloud the problem with students.
- Have students put 21 ones blocks on their desks to represent the number of stickers.
- Write down 0 tens and 21 ones on the board.
- Then, have your students trade 10 ones blocks for 1 tens block.
- Write the number of each type of block under the first answer.
- Finally, direct your students to trade 10 ones blocks for 1 tens block again.
- Discuss the answers and patterns.
- Repeat with another problem. For example: Mary was putting away 42 toys. She can put away the toys in groups of 10 or as single toys. What are the different ways Mary can put away the toys?
Independent working time(15 minutes)
- Ask students to complete some more problems on their own. Great potential questions include: Joe is playing with 19 marbles. He can pick them up in groups of 10 or as singles. What are the different ways that Joe can pick up the marbles?
- Another question could be: Lisa collected 52 plastic tops. She can gather them in groups of 10 or as singles. What are the different ways that Lisa can group the plastic tops?
- Another potential problem includes: Bob needs 30 straws for his project. He can buy them in groups of 10 or as singles. What are the different ways that Bob can buy the straws?
- Enrichment: For advanced students, instruct them to write and solve their own number stories.
- Support: Have your students write their answers in a two-column chart. One column will be for groups of 10 and the second column will be ones. Have students separate their connecting cubes in each column.
- Observe your students, making sure that their responses on the independent assignment are accurate.
Review and closing(5 minutes)
- Ask volunteers to explain how they can show the value of a number in different ways.