Multiplying Decimals by 10, 100, and 1000. Questions from this book are taken
from “Good Questions: Great. Ways to Differentiate Math Instruction.” by Dr.
Multiplying Decimals by 10, 100, and 1000 Questions from this book are taken from “Good Questions: Great Ways to Differentiate Math Instruction.” by Dr. Marian Small Math Learning Goal: • Students will develop strategies for multiplying decimals by 10, 100, and 1000.
60 min
Grade 6 Materials
Big Ideas: • Place value allows us to compare, order, and operate with decimals, using strategies similar to those we use with whole numbers. Curriculum Expectations: • multiply and divide decimal numbers by 10, 100, 1000 and 10 000 using mental strategies
Part One: Mind’s On 5 min.
Part 2: Action!
35 min.
Small Group: Open Question • “The product of two numbers is 2.5. What two numbers might you have multiplied? What word problem might you have been solving?
• question posted on chart paper or Smart Board
Students will discuss this with their partners and then share their responses with the group. Pairs: Parallel Task: • students will work in pairs to complete the following parallel task
• questions posted on chart paper or smart board Choice A: Use a calculator to find the mass of 10, • calculators 100, 1000, and 10 000 of each coin. Record your answers in the place value chart. What patterns do • grocery flyers • place value you notice? charts • chart paper Penny: 2.35 g & markers Nickel: 3.95 g Dime: 1.75 g Quarter: 4.4 g Choice B: Choose 5 products from the grocery flyer. Use mental math (no calculator!) to find the cost of 10, 100, 1000, and 10 000 of each item. Record your answers in a place value chart. What patterns do you notice?
Pairs / Whole Group: Math Congress teacher will choose a few samples of student work • Part 3: and post them on the board to discuss with the Consolidate/ class. Debrief • the teacher will ask students to explain the patterns they found when multiplying by 10, 100, 1000, or 10 000 • teacher will ask students why this might be helpful to know
20 min
Highlights & Summary of Learning: • when we multiply a decimal by 10, the digits shift 1 place to the left. We show this by moving the decimal point one place to the right. • when you multiply a decimal by 100, the digits shift 2 places to the left. We show this by moving the decimal point 2 places to the right. • when we multiply by 1000, the digits shift 3 places to the left. We show this by moving the decimal 3 places to the right. • when we multiply by 10 000, the digits shift 4 places to the left. We show this by moving the decimal 4 places to the right. Question for Further Consolidation • Math Makes Sense pg 139 #1 and “Reflect”
• place value chart
Thousands
Hundreds
Tens
Ones
and
Tenths
Hundredths
Thousandths
