Question

Estimate the total weight of two boxes that weigh 9.4 and 62.6 pounds using rounding and compatible numbers. which estimate is closer to the actual total weight? why?

Answer 1

With rounding:

`4` is less than
`5` so we round it down to whole number:

`9.4\approx9`


`6` is more than
`5` so we round it up to whole number:

`62.6\approx63`

Now we have to add rounded numbers

`63+9=72`

Without rounding:

`62.6+9.4` to make it more visible I will write it differently:


`62+9+0.6+0.4` is equal to
`62.6+9.4`

we can see that
`0.6+0.4` is equal to
`1`

so:

`62+9+1=72`

As you see in this example those equations are equal so it doesn't matter if you take rounded numbers or not, it may be different in case like
`62.4+9.4` (
`0.4` is just an example it could be any other number between
`0-4` ) because in this case it will be equal
`71` and another example
`62.5+9.5` (in this case
`0.5` is just an example, it can be any other number between
`5-9` :) ) and here, answer for this equation is
`73`.