Question

How can you use estimation to find
92 +91 +92 +91 +9?

Answer 1

aprox 280

Explanation:

if you need to add these numbers quickly you can estimate either with an overestimation or under estimation:

for an over estimation, you can find the nearest 10 or 100 that each value is so for this you have 92 + 91 +92 +9 which is close to 100 +100+100+10

so using this you can quickly guess that it would be somewhere around 310

for an under estimation you can do the same thing but rounding down so we instead would add 90 + 90 + 90 + 10 which gives 280

now using both we know the answer would be somewhere between 280 and 310

Answer 2

370

Explanation:

Round each answer into easier to add numbers. 92 and 91 round down to 90. 9 rounds up to 10.