Question

Use rounding or compatible numbers to estimate each product or quotient.

5x2 3/5

about 10
about 10 3/5
about 12
about 15

2. use rounding or compatible numbers to estimate each product or quotient

25 7/8 divided by 2 8/9

about 9
about 10
about 11
about 12

3. Mr. Garcia's class at 3 2/3 pizzas, Mrs Rizzoli's class ate 4 1/8 pizzas, and Mrs. Tindal's class ate 3 1/4 pizzas. Use benchmarks to estimate the total number of pizzas eaten by all three classes.

about 9
about 10
about 11
about 12

Answer 1

Part 1

Using rounding or compatible numbers, we estimate the product


`5*2 (3)/(5)`
to

`5*3`

Therefore, the estimate of the product
`5*2 (3)/(5)`, using rounding and compatible numbers is about 15.



Part 2

Using rounding or compatible numbers, we estimate the quotient


`25(7)/(8)/2 (8)/(9)`
to

`27/3`

Therefore, the estimate of the quotient
`25(7)/(8)/2 (8)/(9)`, using rounding and compatible numbers is about 9.



Part 3

Given that Mr. Garcia's class ate
`3(2)/(3)` pizzas, Mrs Rizzoli's class ate
`4(1)/(8)` pizzas, and Mrs. Tindal's class ate
`3(1)/(4)` pizzas.

Using benchmarks, we estimate the total number of pizzas eaten by all three classes as follows:
`3(3)/(4)`,
`4` and
`3(1)/(4)`

Thus, the total number of pizzas eaten by all three classes is given by


`3(3)/(4)+4+3(1)/(4)=11`

Therefore, the total number of pizzas eaten by all three classes is about 11.