Find one tenth of 7.56 by calculating 7.56 × 0.1.
Multiplying by 0.1 or 0.01
Watch for: Believing multiplication must make a positive number larger.. Explain what the quantities mean before calculating.
Opening task
Prerequisite check
What is 1/10 of 20?
Show worked answer (after attempting)
20 ÷ 10 = 2.
Understand the idea
Interpret multiplication by 0.1 and 0.01 as one-tenth or one-hundredth of a positive number. The essential earlier idea is: 5A fraction multiplication and Chapter 9 decimal equivalence.. The model below will always use the actual quantities from the worked problem. Check believing multiplication must make a positive number larger when you explain your answer.
Three worked examples
Worked example 1 · MATH-5B-C10-L03-Q01
Find one tenth of 7.46 by calculating 7.46 × 0.1.
Solution: 0.746
0.1 is one tenth. Therefore 7.46 × 0.1 = 0.746, smaller than the starting positive amount.
Worked example 2 · MATH-5B-C10-L03-Q02
A container holds 4.5 L. What is one hundredth of this capacity?
Solution: 0.045 L
0.01 is one hundredth. Therefore 4.5 × 0.01 = 0.045, smaller than the starting positive amount.
Worked example 3 · MATH-5B-C10-L03-Q03
Explain whether 0.83 × 0.1 should be greater or less than 0.83 and calculate.
Solution: 0.083
0.1 is one tenth. Therefore 0.83 × 0.1 = 0.083, smaller than the starting positive amount.
Check understanding
Find one tenth of 7.56 by calculating 7.56 × 0.1.
Show worked answer (after attempting)
0.1 is one tenth. Therefore 7.56 × 0.1 = 0.756, smaller than the starting positive amount.
A container holds 4.6 L. What is one hundredth of this capacity?
Show worked answer (after attempting)
0.01 is one hundredth. Therefore 4.6 × 0.01 = 0.046, smaller than the starting positive amount.
Explain whether 0.93 × 0.1 should be greater or less than 0.93 and calculate.
Show worked answer (after attempting)
0.1 is one tenth. Therefore 0.93 × 0.1 = 0.093, smaller than the starting positive amount.
Guided practice
Find one tenth of 7.66 by calculating 7.66 × 0.1.
Show worked answer (after attempting)
0.1 is one tenth. Therefore 7.66 × 0.1 = 0.766, smaller than the starting positive amount.
A container holds 4.7 L. What is one hundredth of this capacity?
Show worked answer (after attempting)
0.01 is one hundredth. Therefore 4.7 × 0.01 = 0.047, smaller than the starting positive amount.
Explain whether 1.03 × 0.1 should be greater or less than 1.03 and calculate.
Show worked answer (after attempting)
0.1 is one tenth. Therefore 1.03 × 0.1 = 0.103, smaller than the starting positive amount.
Find one tenth of 7.76 by calculating 7.76 × 0.1.
Show worked answer (after attempting)
0.1 is one tenth. Therefore 7.76 × 0.1 = 0.776, smaller than the starting positive amount.
Independent practice
A container holds 4.8 L. What is one hundredth of this capacity?
Show worked answer (after attempting)
0.01 is one hundredth. Therefore 4.8 × 0.01 = 0.048, smaller than the starting positive amount.
Explain whether 1.13 × 0.1 should be greater or less than 1.13 and calculate.
Show worked answer (after attempting)
0.1 is one tenth. Therefore 1.13 × 0.1 = 0.113, smaller than the starting positive amount.
Find one tenth of 7.86 by calculating 7.86 × 0.1.
Show worked answer (after attempting)
0.1 is one tenth. Therefore 7.86 × 0.1 = 0.786, smaller than the starting positive amount.
A container holds 4.9 L. What is one hundredth of this capacity?
Show worked answer (after attempting)
0.01 is one hundredth. Therefore 4.9 × 0.01 = 0.049, smaller than the starting positive amount.
Explain whether 1.23 × 0.1 should be greater or less than 1.23 and calculate.
Show worked answer (after attempting)
0.1 is one tenth. Therefore 1.23 × 0.1 = 0.123, smaller than the starting positive amount.
Find one tenth of 7.96 by calculating 7.96 × 0.1.
Show worked answer (after attempting)
0.1 is one tenth. Therefore 7.96 × 0.1 = 0.796, smaller than the starting positive amount.
A container holds 5 L. What is one hundredth of this capacity?
Show worked answer (after attempting)
0.01 is one hundredth. Therefore 5 × 0.01 = 0.05, smaller than the starting positive amount.
Explain whether 1.33 × 0.1 should be greater or less than 1.33 and calculate.
Show worked answer (after attempting)
0.1 is one tenth. Therefore 1.33 × 0.1 = 0.133, smaller than the starting positive amount.
Challenge and error analysis
The assigned question is: “A container holds 5.3 L. What is one hundredth of this capacity?” A learner wrote: “5.3 × 0.01 = 0.153. I used this intermediate value to finish the assigned problem.” Identify a concrete invalid step or assumption. Work out the correct result and explain why it is valid.
Show worked answer (after attempting)
The attempted reasoning or reported result does not satisfy the specified operation, units or geometric conditions. Correct mathematical result: 0.053 L. Recompute from the given data: 0.01 is one hundredth. Therefore 5.3 × 0.01 = 0.053, smaller than the starting positive amount.
The assigned question is: “Explain whether 1.63 × 0.1 should be greater or less than 1.63 and calculate.” A learner wrote: “1.63 × 0.1 = 1.163. I used this intermediate value to finish the assigned problem.” Identify a concrete invalid step or assumption. Work out the correct result and explain why it is valid.
Show worked answer (after attempting)
The attempted reasoning or reported result does not satisfy the specified operation, units or geometric conditions. Correct mathematical result: 0.163. Recompute from the given data: 0.1 is one tenth. Therefore 1.63 × 0.1 = 0.163, smaller than the starting positive amount.
Exit check
Find one tenth of 8.06 by calculating 8.06 × 0.1.
Show worked answer (after attempting)
0.1 is one tenth. Therefore 8.06 × 0.1 = 0.806, smaller than the starting positive amount.