06-NelsonMathGr5-Chap06
6/26/04
11:21 AM
Page 172
CHAPTER 6
You will need
7
Estimating Quotients
Goal
Reflecting
• a calculator
1. Why do you think Sofia said that the total amount of
rain would be higher than her school?
Overestimate and underestimate
when dividing.
2. How do you know that the daily amount of rain is
greater than 0.5 m?
Sofia is doing a report on extreme
weather for Science class.
She discovers that, in La Réunion Island,
it once rained 4653 mm in six days.
She thinks this amount of water is
higher than her school! She wants to
estimate the number of millimetres of
rain for each day.
3. Imagine that 4653 mm of rain fell in five days instead
of in six days. What numbers might you choose for
overestimating and underestimating? Explain.
4. Why does it make more sense to estimate than
to calculate the amount of rainfall each day?
Checking
? About how many millimetres of
5. In one eight-day period, 5286 mm of rain fell on
La Réunion Island.
a) Show how to overestimate and underestimate
the amount of rain that fell each day.
b) Explain how you can use your two estimates
to make a closer estimate.
rain fell each day?
Sofia’s Estimates
I’ll make two estimates for the number of millimetres
of rain that fell each day.
Practising
6. Estimate to solve each problem. Explain your reasoning.
a) The total attendance at a powwow in July was
5208 people in 7 days. The total attendance
at a powwow in August was 2934 in 3 days.
Which powwow had the greater daily attendance?
b) A movie store rented 3354 DVDs in 2 days and 4487
VHS tapes in 3 days. Which type of movie had the
greater daily rental?
c) The cost of 6 televisions is $5136. The cost of
5 computer monitors is $3195. Which item costs more?
First I’ll underestimate, and then I’ll overestimate.
The answer will be between these two estimates.
First I’ll divide 4200 by 6. Then I’ll divide 4800 by 6.
A. Complete Sofia’s two estimates. Explain how to use
mental math to divide 4200 by 6 and 4800 by 6.
B. Why do you think Sofia chose the numbers 4200 and
4800 for her two estimates?
7. Overestimate and underestimate each division.
Show the numbers you used to estimate.
C. When you divide 4653 by 6, do you think the answer is
closer to your underestimate, closer to your overestimate,
or about halfway in between? Explain your reasoning.
172
NEL
NEL
a) 21
5
1
2
c) 34
2
1
8
e) 63
3
5
5
b) 96
6
5
5
d) 85
8
4
6
f) 75
2
3
8
173
06-NelsonMathGr5-Chap06
6/26/04
11:21 AM
Page 172
CHAPTER 6
You will need
7
Estimating Quotients
Goal
Reflecting
• a calculator
1. Why do you think Sofia said that the total amount of
rain would be higher than her school?
Overestimate and underestimate
when dividing.
2. How do you know that the daily amount of rain is
greater than 0.5 m?
Sofia is doing a report on extreme
weather for Science class.
She discovers that, in La Réunion Island,
it once rained 4653 mm in six days.
She thinks this amount of water is
higher than her school! She wants to
estimate the number of millimetres of
rain for each day.
3. Imagine that 4653 mm of rain fell in five days instead
of in six days. What numbers might you choose for
overestimating and underestimating? Explain.
4. Why does it make more sense to estimate than
to calculate the amount of rainfall each day?
Checking
? About how many millimetres of
5. In one eight-day period, 5286 mm of rain fell on
La Réunion Island.
a) Show how to overestimate and underestimate
the amount of rain that fell each day.
b) Explain how you can use your two estimates
to make a closer estimate.
rain fell each day?
Sofia’s Estimates
I’ll make two estimates for the number of millimetres
of rain that fell each day.
Practising
6. Estimate to solve each problem. Explain your reasoning.
a) The total attendance at a powwow in July was
5208 people in 7 days. The total attendance
at a powwow in August was 2934 in 3 days.
Which powwow had the greater daily attendance?
b) A movie store rented 3354 DVDs in 2 days and 4487
VHS tapes in 3 days. Which type of movie had the
greater daily rental?
c) The cost of 6 televisions is $5136. The cost of
5 computer monitors is $3195. Which item costs more?
First I’ll underestimate, and then I’ll overestimate.
The answer will be between these two estimates.
First I’ll divide 4200 by 6. Then I’ll divide 4800 by 6.
A. Complete Sofia’s two estimates. Explain how to use
mental math to divide 4200 by 6 and 4800 by 6.
B. Why do you think Sofia chose the numbers 4200 and
4800 for her two estimates?
7. Overestimate and underestimate each division.
Show the numbers you used to estimate.
C. When you divide 4653 by 6, do you think the answer is
closer to your underestimate, closer to your overestimate,
or about halfway in between? Explain your reasoning.
172
NEL
NEL
a) 21
5
1
2
c) 34
2
1
8
e) 63
3
5
5
b) 96
6
5
5
d) 85
8
4
6
f) 75
2
3
8
173