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Sample Answers
5. Answers will vary.
a) A paper clip
b) Chalkboard eraser
c) Paperback book
d) Hardcover textbook
6. a) 0.5 t, 500 000 g
b) 850 000 mg, 0.85 kg
c) 4 300 000 mg, 4.3 kg d) 2100 kg, 2 100 000 g
7. A grade 6 student might have mass 40 kg.
Since 1 t is equivalent to 1000 kg, divide 1000 by 40.
Twenty-five 40-kg students have a total mass of about 1 t.
8. Five kilograms is 5000 g.
One-fifth of 5000 g is 1000 g.
One-fourth of 5000 g is 1250 g.
One-fourth of 5000 g is the greater mass.
9. a) Yes, it is safe. The mass on the elevator before the two
people get on is 370 kg. If the two people get on, the
total mass would be 504 kg or 0.504 t.
b) There might not be room for the two people to fit on
the elevator.
11. I would measure the mass of the empty jar, then measure the
mass of the full jar and find the difference. The difference in
mass is equal to the mass of the 500 marbles. Then I would
divide the mass by 500 to get the mass of 1 marble.
Review the examples in Connect. To reinforce
that 1 mg equals 0.001 g, show students a unit
cube and a thousands cube. Establish that the
thousands cube represents 1 whole.
Demonstrate that 1 mg is related to 1 g in the
same way that a unit cube is related to the
thousands cube.
1
1000
Grams
Kilograms
100 000 mg
0.05 g
76 000 g
650 g
Milligrams
Tonnes
88 000 mg
500 mg
5.5 g
6000 mg
0.432 kg
2.5 kg
7620 kg
12.535 t
1800 kg
1.2 kg
170 g
30 kg
Practice
Advise students to refer to the examples in
Connect when converting between units of mass.
Have calculators available for question 10.
Question 5 requires balance scales and
standard masses.
Question 7 requires metric bathroom scales.
1 unit cube is , or 0.001, of the thousands
1
1000
cube. 1 milligram is , or 0.001, of a gram.
Discuss situations when an estimate of mass
is acceptable and when a precise measurement
is needed. Ask:
• When might an estimate of a mass be used?
(When feeding my dog, the mass of food I give him
in grams depends on his mass in kilograms.)
• When might a precise measurement of mass
be needed?
(When a baby is sick, the dose of medicine given
depends on the mass of the baby. You must be precise or
else the baby will get too little or too much medicine.)
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Unit 9 • Lesson 6 • Student page 346
Assessment Focus: Question 8
Students could convert one mass so that both
measurements are in the same units. Some
students may recognize that one-fifth of 5 kg
is 1 kg or 1000 g. Other students may
benefit from drawing a picture to explain
their thinking.
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REFLECT: I divide to convert from smaller to larger units of mass
and multiply to convert from larger to smaller units of mass.
For example, to convert 3 kg to grams, I am converting from
a larger unit of mass to a smaller unit, so I multiply 3 by
1000 to get 3000 g. To convert 2000 mg to grams, I am
converting from a smaller unit of mass to a larger unit, so
I divide 2000 by 1000 to get 2 g.
Yes
At Home
About 50
23 871.25 cm3
378.3 cm2
About 500 cm2
Students may find tools such as tape measures, bathroom scales,
or measuring cups at home. They should be able to describe
several things that can be measured with each tool. For example,
a tape measure can measure the length of a wall, bathroom
scales can measure the mass of a person, and a measuring cup
can measure the volumes of ingredients in a recipe.
Making Connections
Math Link: Have students research the process used to make
a toonie. Alternatively, challenge students to find out which
materials make up each Canadian coin. Have students present
their findings to the class.
Numbers Every Day
Students need to determine that one week has 168 h and one
decade has about 3650 days.
• Ten thousand $100 bills
• About 5952 weeks
• About 274 decades
ASSESSMENT FOR LEARNING
What to Look For
What to Do
Reasoning; Applying concepts
✔ Students understand the relationships
among milligrams, grams, kilograms,
and tonnes.
Extra Support: Students may find it helpful to use play
money when they complete Explore. Use Base Ten Blocks to
reinforce the relationships among units of mass.
Students can use Step-by-Step 6 (Master 9.15) to complete
question 8.
Accuracy of procedures
✔ Students can select an appropriate
unit to estimate and measure mass.
Communication
✔ Students can explain how to convert
among milligrams, grams, kilograms,
and tonnes.
Extra Practice: Students can complete the Additional Activity,
Mass Target (Master 9.10).
Students can complete Extra Practice 3 (Master 9.20).
Extension: Have students use the table in Explore to calculate
how many of each coin would make 1 t, and the corresponding
value of the money.
Recording and Reporting
Master 9.2 Ongoing Observations:
Measurement
Unit 9 • Lesson 6 • Student page 347
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