Take it to the Bank!
Students will be able to compare two decimals to the hundredths place.
- Before beginning this lesson, make sure to review decimal place values (tenths and hundredths) with your students.
- Review the symbols used for comparing numbers ( >, <, = ).
- Explain, "Today we are going to compare numbers with decimals using these symbols." Remind students that when we compare numbers we are looking at the difference in value between two (or more) numbers.
Explicit Instruction/Teacher modeling(10 minutes)
- Write two decimals on the board (i.e. 0.34 and 0.51) and explain that when we compare decimals, we can use the strategies that we use to compare whole numbers. Remind students that, when comparing numbers, we compare the digits from left to right.
- Draw a place value chart on the board (see resources). Then, write one decimal on the first row and the other on the second row. Compare each place value, moving from left to right.
- Write "0.34 < 0.51" on the board. Explain that since five-tenths is greater than three-tenths, 0.51 is greater than 0.34.
- Show students two different amounts of money, holding $0.81 in one hand and $0.69 in the other. In front of students, count out the change in each hand and write the two numbers on the board.
- Draw a place value chart and lead students through another example, this time comparing the value of the coins.
Guided Practice(10 minutes)
- Lead students through another example, asking for student input as your solve (i.e. 1.7 and 1.27). Discuss the value of the tenths place in each number and be sure to remind students that, after the decimal place, zeros can be added to the right of the existing digits without changing the value of the number.
- Show students two different amounts of money (i.e. $1.09 and $1.25). Have them work with a partner to draw a place value chart and solve. Discuss the problem with the class when finished.
Independent working time(13 minutes)
- Write three problems (three sets of numbers to compare) on the board. Instruct students to solve using a place value chart, showing their work in a math notebook or on scratch paper.
- Possible problems may be 5.2 and 5.15; 0.78 and 0.87; 0.19 and 0.1
- When students are finished, place two cups of coins (or coin manipulatives) with each group of students. Instruct students to compare the amounts of money in each cup, using place value charts to show their work.
- Circulate and offer support as needed.
- Reteach a lesson on comparing whole numbers.
- Provide additional examples during guided practice.
- Have students apply the comparing numbers skills learned in this lesson to solve word problems with decimal numbers.
- Hand out five blank index cards to each student. Instruct students to write a decimal on each card in large handwriting. Do not tell them what the cards are for until after all the cards are completed.
- Give parameters: Numbers may have up to two digits after the decimal point and one digit, which can be a zero, before the decimal point. Each card must be different.
- Have students pair up and use their cards to play the card game known as war. Holding their cards face down, each partner flips over one card at the same time. The person who played the card with the greater value wins the round. Partners play until all cards have been flipped.
- Have students find a new partner when they have finished a game (all five cards have been flipped).
- Circulate and observe to gauge student understanding.
Review and closing(5 minutes)
- Ask and discuss:
- What are some real world situations when you might need to compare numbers with decimals? (i.e. which item costs more at the grocery store, which baseball player has a better ERA)
- What are some similarities and differences between comparing whole numbers and comparing decimals? (i.e. you can use the same strategies to compare; with whole numbers, a number with more digits will be greater, but when comparing decimals, a number with fewer digits could be greater)