Estimate the difference 2, 18,367-5
and compare the result with the actual
difference.
Answers
Step-by-step explanation:
many practical calculations, only an approximation is required rather than an exact answer. To do this, numbers are rounded off to a given place value of ten, hundred, thousand ...
Example on Estimating Sums:
1. There are 74 coconut cookies and 48 chocolate cookies in a jar. Estimate the total number of cookies.
Round the numbers to the nearest ten and add.
Rounded to TENS
Estimating Sums
2Save
There are approximately 120 cookies.
The actual number of cookies is 122.
The estimate differs from the actual by 2.
2. There are 275 students in class IVth and 238 students in class Vth. Estimate the total number of students in the two classes.
We can round the numbers either to the nearest ten or the nearest hundred and add to get an estimate.
Rounded to TENS
Estimating
2Save
There are approximately 520 students.
The estimate differs from the actual by 7.
Rounded to HUNDREDS
Rounded to HUNDREDS
2Save
There are approximately 500 students.
The estimate differs from the actual by 13.
Estimating Difference:
Example on Estimating Difference:
The school library has 284 science books and 268 social sciences books.
Estimate the difference in the number of books.
Rounded to TENS
Estimating Difference
2Save
The difference is approximately 20 books.
The estimate differs from the actual number by 4.
Rounded to HUNDREDS
Rounded nNumbers
2Save
In this case, rounding number to hundreds will not be meaningful as the difference will be 0.
Examples on estimating sums and differences of the numbers:
1. The number of students in Classes III, IV and V are 154,129 and 118. Estimate the total number of students in the three classes taken together.
Solution:
The rounded numbers are used to estimate.
So 154 ⇒ 200 being more than 150
129 ⇒ 100 being less than 150
118 ⇒ 100 being less than 150
400 So total number as estimated is 400
[Note: Actual number is 401, which is one more than 400]
Answer: 400