Question

Explain how to round numbers 33 and 89 to estimate their sum

Answer 1

Solution 

 Method 1 - Round off the numbers to the nearest tens. (check the one's place digit for rounding off)

33 is rounded off to 30  -------( 3 < 5 so replace it by 0)
89 is rounded off to 90  -------( 9 > 5 so add 1 to ten's place digit i.e. 8+1 = 9 and replace one's place by 0)

Estimated Sum = 30 + 90
                          = 120

Answer 2

Solution :-

Round off 33 and 89 to their Tens place value.

In 33, the digit at one's place is less than 5. So. 33 will become 30

33 = 30

In 89, the digit at one's place is more than 5, so 89 will become 90

89 = 90 

Estimated sum -

30 + 90 = 120

Answer.