Human Number Line
Students will be able to compare and order decimals to the thousandths place value.
- Show the Ordering Decimals video by Numberock to review comparing decimals.
- Tell students that today we are going to compare and order numbers with decimals.
- Remind students that when we compare numbers we are looking at the difference in value between two or more numbers. Then, explain that ordering decimals involves putting decimals in order according to their value.
Explicit Instruction/Teacher modeling(10 minutes)
- Write three decimals on the board (i.e. 0.29, 0.93, and 0.41) and explain that when we order decimals, we can use some of the same the strategies that we use to compare numbers, like place value charts.
- Remind students that, when comparing numbers with a place value chart, we compare the digits from left to right.
- Draw a place value chart on the board with as many rows as there are numbers (see linked example if needed). Then, write one decimal in each row.
- Compare the numbers at each place value, moving from left to right to determine the order of the numbers from greatest to least, then rewrite the numbers in descending order (0.93, 0.41, 0.29).
- Draw a place value chart and lead students through another example, this time ordering numbers from least to greatest (i.e. 0.127, 0.35, 0.098, 0.5).
- 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.
Guided Practice(10 minutes)
- Lead students through another example, asking for student input as you solve (i.e. 1.236, 1.49, 0.958, 2.01).
- Write another group of numbers on the board (i.e. 0.32, 0.46, 0.046, 0.3) and instruct students to order them from greatest to least. 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(10 minutes)
- Write three problems (three sets of numbers to order) on the board. Be sure to indicate whether numbers should be ordered least to greatest or greatest to least. Instruct students to solve using a place value chart for each problem, showing their work in a math notebook or on scratch paper. Possible problems include:
- 1.51, 1.467, 1.8
- 0.924, 0.9, 0.09, 0.429
- 2.6, 2.33, 1.92, 2.074
- Circulate and offer support as needed.
- Reteach a lesson on comparing two numbers.
- Provide additional examples during guided practice.
- Have students apply the skills learned to solve word problems.
- Hand out four 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 three digits after the decimal point and one digit, which can be a zero, before the decimal point. Each card must be different.
- Collect all the cards and shuffle them. Then, hand out four random cards to each student. Instruct students to draw a place value chart to order their cards from greatest to least.
- Collect the cards, shuffle, and redistribute. Instruct students to use a place value chart to order their new cards in order from least to greatest.
- While students work, circulate and observe to gauge understanding.
Review and closing(10 minutes)
- Collect all the decimal cards used during the assessment activity and pass out one card only to each student.
- Tell students, we are going to work together as a class to order all of the numbers on our cards. When we are done, we will have a human number line!
- Choose five students to stand at the front of the room, with their cards displayed in order (least to greatest). Have them spread apart to leave room for other students to join. (Hint: Try to pick a low number and high number among the five students).
- Invite five students at a time to come join the number line, finding their spot by comparing their own number to those already displayed.
- Support students as needed during this activity and encourage students to help one another as well.