Question

Explain how to estimate 368+231 two different ways

Answer 1

we know that

One very simple form of estimation is rounding.

To round off whole numbers:

Find the place value you want (the "rounding digit") and look to the digit just to the right of it.

If that digit is less than $5$, do not change the "rounding digit" but change all digits to the right of the "rounding digit" to zero.

If that digit is greater than or equal to $5$, add one to the rounding digit and change all digits to the right of the rounding digit to zero.

Part a) Estimate$(368+231)$ rounding the numbers to nearest hundreds

$368$

$368 > 350$ ------> round up to $400$

$231$

$231 < 250$ ------> round down to $200$

so

$(368+231)=400+200=600$

therefore

the answer part a) is

$600$

Part b) Estimate $(368+231)$ rounding the numbers to nearest tens

$368$

$68 > 65$ ------> round up to $370$

$231$

$31 < 35$ ------> round down to $230$

so

$(368+231)=370+230=600$

therefore

the answer part b) is

$600$

Answer 2

You can estimate 368 + 231 by rounding the numbers to nearest hundreds
Which is 400 + 200
You can estimate 368 + 231 by rounding the numbers to the nearest tens
Which is 370 + 230