UPSKILL MATH PLUS
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Learn moreGeneral rule for rounding:
- If the number ends up with 5, 6, 7, 8 or 9, then round the number up (nearest tens).
- If the number ends up with 1, 2, 3 or 4, then round the number down (nearest tens).
Example:
Consider the numbers 13 and 18.
Let us rounding the numbers to nearest tens.
Note that 13 ends up with 3 and 18 is end up with 8.
Consider 13,
Here the tens digit is 1, and the unit digit is 3, which is lesser than 5.
So leave the tens place unchanged and change the digits to the right of 1 to zero.
That is the rounding the number 13 results in 10.
Consider 18,
Here the tens digit is 1, and the unit digit is 8, which is greater than 5.
As the right of the tens digit is greater than 8, add 1 to it. That is 1+1=2.
Now change the digits to the right of 2 to zero.
That is the rounding the number 18 results in 20.
Here come the number line for the numbers 13 and 18.
It can be concluded that both 13 and 18 lies between 10 and 20.
The number 13 is nearer to 10 than 20, and the number 18 is nearer to 20 than 10.
Therefore, the nearest tens place of 13 and 18 are 10 and 20.
Thus, let us see the procedure for rounding the number to the nearest tens.
Step 1: Find the digits in the tens place.
Step 2: Determine the digit to its right.
Step 3: If this digit is 5 or greater, add 1 to it. If it is lesser, then leave it as it is.
Step 4: Make the digits to the right of tens place to zero.
Now try to round off 124 to nearest tens.
Estimating 124 to the nearest tens = 120.
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