55 + 33 = _________. 

21 + 36 = ______.

 33 = 3 tens and _____ ones. 

The place value of a digit multiplied by the digit itself and added to all the digit given gives the number.

Round the number 6657 to the nearest hundred.

For rounding off to nearest hundred, we can also look at the number formed by the tens place and the units place digit. If the number is 50 or more, we rounded up. If the number is less than 50 we rounded down.

Remo drove his motorcycle 325 miles on Friday, 119 miles on Saturday and 465 miles on Sunday. The best estimate of the number of miles he drove over the 3 days is_______.

We can also add all the 3 distance at first and then use front end estimation.
Here, 325 + 119 + 465 = 909  which when rounded off to nearest hundred gives 900.

54 + 23=_____.

Add  the digits of the same place value of all numbers and write the resultant.

The leading digit in 2534 is ________. 

In the question, we need to find the leading digit of the number. The first digit of the number is the leading digit.

Round the number 265 to the nearest hundred.

last two numbers in 265 is 65 and 65 is greater than equal to 50 so, round off to nearest hundred greater than 265.
So, 265 rounds off to 300.

Estimate the difference between 9438 – 4519 to nearest hundred, and check the reasonableness.

Step 1 : Round Off ;

if last 2 digits are more than or equal to 50, round off to nearest hundred greater than number .

if last 2 digits are less than 50, round off to nearest hundred  smaller than number.

9438 rounds off to 9400.

4519 rounds off to 4500.

Step 2 : Perform Subtraction  

9400 - 4500 = 4900

4900 is very close to actual result with a difference of about  1% so it is, reasonable.
 

Estimate the sum of 7300 + 5315 nearest to hundred and then check that the answer is reasonable or not. 

Step 1 : Round Off ;

if last 2 digits more than or equal to 50 round off to nearest hundred greater than number.

if last 2 digits less than 50 round off to nearest hundred smaller than number.

5315 rounds off to 5300.

7300 rounds off to 7000.

Step 2 : Perform Addition 

5300 + 7000 = 12,300 ;

12300 is very close to actual sum with a difference of less than 1% so it is , reasonable.

The difference of 516 and 140 using front-end estimation is ________. 

Step 1 :
In 516, five is the first number and in 140, 1 is first number or front number so simply add them.
5 - 1 = 4 as they are at hundredth place so 400
next , 16 to nearest hundred is 0 and 40 to nearest 100 is 0 .
0 - 0 = 0 ;
Step 2 :
add all estimations 400 + 0 ;
So , 400 is our final answer.

There are 479 girls and 729 boys in a school. Estimate the total number of students in the school. 

The difference of 587 and 222 using front -end estimation is ________. 

The sum of 730 + 450 using front – end estimation is______. 

The number of students in Classes III, IV and V are 155,139 and 118. Estimate the total number of students in the three classes taken together. 

The school library has 285 science books and 268 social science books. Estimate the difference in the number of books.