Question

Explain how an estimate helps you place the decimal point when multiplying 3.9 × 5.3

Answer 1

An estimate helps you because you round 3.9 to 4 and 5.3 to 5 so then you can give a rough estimation

Answer 2

`3.9* 5.3\approx 20`

Explanation:

To find : How an estimate helps you place the decimal point when multiplying
`3.9* 5.3` ?

Solution :

Estimate the number 3.9 by rounding to ones,

As tenth place 9 >5 ones place round by 1.

So,
`3.9\approx 4`

Estimate the number 5.3 by rounding to ones,

As tenth place 3<5 ones place remain same.

So,
`5.3\approx 5`

`3.9* 5.3\approx 4* 5`

`3.9* 5.3\approx 20`

Therefore,
`3.9* 5.3\approx 20`