Question

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

- 17
- 16
- 20
- 10

Hint:

### We have to find the estimated difference between the science and social science books in library. Subtracting these numbers we get the the difference and after rounding off we get the required number i.e. the estimated difference between number of science and social science books in library.

## The correct answer is: 20

### number of science books = 285

number of social science books = 268

Difference between the number of books

= 285-268

= 17

Rounding off 17 = 20

So, 20 is the estimated difference between science and social science books in library.

### Related Questions to study

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### The sum of 440 and 560 using front – end estimation is ______.

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### Estimate the sum of 5786 and 2126 to the nearest thousands.

Step 1 : Round Off ;

if last three digits are more than or equal to 500 round off to nearest thousand greater than number.

5786 rounds off to 6000.

if last three digits less than 500, then round off to nearest thousand smaller than number.

2126 rounds off to 2000.

Step 2 : Perform Addition

6000 + 2000 = 8000 ;

So , 8000 is our estimated sum .

### Estimate the sum of 5786 and 2126 to the nearest thousands.

Step 1 : Round Off ;

if last three digits are more than or equal to 500 round off to nearest thousand greater than number.

5786 rounds off to 6000.

if last three digits less than 500, then round off to nearest thousand smaller than number.

2126 rounds off to 2000.

Step 2 : Perform Addition

6000 + 2000 = 8000 ;

So , 8000 is our estimated sum .

### Estimate the difference between 7123 and 3678 to the nearest thousands.

Step 1 : Round off

If last 3 digits are less than 500 than round off to nearest 1000 less than the number .

so, 7123 rounds off to 7000 .

If last 3 digits are greater than or equal to 500 than round off to nearest 1000 greater than the number.

so, 3678 rounds off to 4000 .

Step 2 : On performing subtraction

7000 - 4000 = 3000 ;

So, 3000 is our estimated answer.

### Estimate the difference between 7123 and 3678 to the nearest thousands.

Step 1 : Round off

If last 3 digits are less than 500 than round off to nearest 1000 less than the number .

so, 7123 rounds off to 7000 .

If last 3 digits are greater than or equal to 500 than round off to nearest 1000 greater than the number.

so, 3678 rounds off to 4000 .

Step 2 : On performing subtraction

7000 - 4000 = 3000 ;

So, 3000 is our estimated answer.

### The leading digit in 8574 is ________.

Here, 8 is the first digit as well as non-zero number, so leading digit in 8754 is 8 .

### The leading digit in 8574 is ________.

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