Lesson 3.2 Estimating Products and Quotients

Lesson 3.2 Estimating Products and Quotients

Lesson and Assignment

Multiple Choice

Which one will provide the closest benchmark estimation for 8.97 x 5.98?

• 8 x 5

• 9 x 6

• 8 x 6

• 9 x 5

Multiple Choice

Which one will provide the closes benchmark estimation for 1.59 x 10.27?

• 2 x 10

• 2 x 11

• 1 x 10

• 1 x 11

Multiple Choice

For this question, would it be best to use decimal benchmarks or front-end estimation for the product of 99.98 x 2.05?

• 100 x 2

  decimal benchmarks

• 99 x 2

  front-end rounding

Decimal Benchmarks would be best because

• 99.98 is very close to 100

• 2.05 is very close to 2

• 100 x 2 = 200 which is a very close estimate. It's also easier mental math.

Multiple Choice

Which one will provide the closes benchmark estimation for 3.23 x 8.54?

• 4 x 8 = 32

• 3 x 9 = 27

• 3 x 8 = 24

• 4 x 9 = 36

Multiple Choice

Which equation accurately demonstrates the front-end estimation of 1.59 x 13.27?

• 1 x 13 = 13

• 2 x 13 = 26

• 1 x 14 = 14

• 2 x 14 = 28

Front-end estimation uses the whole number and ignores the decimal.

• 1.59 becomes 1

• 13.27 becomes 13

• 1 x 13 = 13

Front-end estimation is a poor choice for 1.59 x 13.27

• 1 x 13 = 13

• 1.59 x 13. 27 = 21. 0993

• This estimate is way too low.

Multiple Choice

Barry paid $29.85 for 2 tickets to the Jazz Festival. Estimate the cost for one ticket.

• $14

• $15

• $16

Use decimal benchmarking to round $29.85 to $30.

• $30 ÷ 2 = $15

• 
  

• 
  

Multiple Choice

Estimate the product of 3.8 x 5 using benchmark estimation. Is this an overestimate or an underestimate?

• 4 x 5 = 20

  which is an overestimate

• 3 x 5 = 15

  which is an underestimate

3.8 x 5

• 3.8 is closer to 4 than to 3

• Round 3.8 up to 4

• 4 x 5 = 20

• 3.8 x 5 = 19

• 20 is a reasonable answer.

Multiple Choice

Estimate the quotient of 12.31 ÷ 2.9 using front-end estimation. Is this an underestimate or an overestimate?

• 13 ÷ 2 = 6.5

  which is an underestimate

• 12 ÷ 3 = 4

  which is an underestimate

• 12 ÷ 2 = 6

  which is an underestimate

Compensation can be used by estimating one number up and one number down. For 12.31 ÷ 2. 9 this would give us a much closer estimate.

• 12 ÷ 3 = 4

• Actual answer:

  12.31 ÷ 2.9 = 4. 24

Multiple Choice

A pair of ice cleats for ice fishing costs $14.89. About how much will 5 pairs cost?

• ~ $70.00

• ~ $75.00

• ~ $ 72.00

$14.89 x 5

• Use decimal benchmarks

• Round $14.89 is closer to $15.00 than $14.00

• $15.00 x 5 = $75.00

• $14.89 x 5 = $74.45

• $75.00 is very close.

Multiple Choice

15 players from the Royal Wildcats went to buy lunch together and spent $87.85. About how much money did the team spend for each player?

• ~ $5.00

• ~ $7.00

• ~ $6.00

• ~ $9.00

Use decimal benchmarks for the closes answer.

• $87.85 ÷ 15

• $87.85 is closer to $90.00 than $80.00 or even $85.00

• $90 ÷ 15 = $6.00

• Actual answer: $87.85 ÷ 15 = $5.86

• $6.00 is a reasonable answer.