How do you estimate $41 times 58$ by rounding?

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Answer 1 · 2016-11-20T09:36:59

$41xx58 ~~ 40xx60 = 2400$

Rounded to the nearest $10$ we have:

$41 ~~ 40$

$58 ~~ 60$

So:

$41 xx 58 ~~ 40 xx 60$

To multiply $40$ and $60$ we just need to multiply $4xx6$ then add $2$ zeros:

$40xx60 = (4xx10)xx(6xx10)$

$color(white)(40xx60) = 4xx6xx10xx10$

$color(white)(40xx60) = 24xx100$

$color(white)(40xx60) = 2400$

So

$41xx58~~40xx60=2400$

Actually:

$41xx58 = 2378$

which to the nearest $100$ is $2400$

How do you estimate 41 times 5841 times 58 by rounding?