We can round off the numbers to the:
Rules to Round Off the numbers:
Round Off to The nearest to Ten: If you need to round off a number to the nearest ten, write the multiples of 10 above (after) the number and multiples of 10 below (before) the number and look to which Multiple, the given number is closer. Round off the number to the closest multiple.
Example: Suppose we need to round off 76 to the nearest 10.
Now, round off the given number to the closest multiple of 10 (closest will be the multiple having smaller difference with the given number).
Now, 76 is closer to 80, So 76 rounded off to the nearest 10 = 80
Alternative method: Look at the one’s digit of the number we have to round off,
if One’s digit is 5 or more then round up means add 1 to ten’s digit and make one’s digit zero.
Example: suppose we need to round off 76
One’s digit of 76 is 6 and 6 > 5
So, add 1 to ten’s digit,
which is 7 and by adding 1 to it, we will get 7+1 = 8
And make One’s digit zero,
so 76 rounded off to the nearest 10 = 80
And if One’s digit is less than 5 then round below means make one’s digit zero.
Example: suppose we need to round off 74
One’s digit of 74 is 4 and 4 < 5
So, make One’s digit zero,
now 74 rounded off to the nearest 10 = 70
Round Off to The nearest to Hundred: If you need to round off a number to the nearest hundred, write multiple of 100 above (after) the number and multiple of 100 below (before) the number and look to which Multiple, the given number is closer. Round off the number to the closest multiple.
Example: Suppose we need to round off 176 to the nearest 100.
Now, round off the given number to the closest multiple of 100 (closest will be the multiple having smaller difference with the given number).
So, 176 is closer to 200,
176 rounded off to the nearest 100 = 200
Alternative method: Look at the ten’s digit of the number we have to round off,
if Ten’s digit is 5 or more then round up means add 1 to hundred’s digit and make ten’s digit and one’s digit zero.
Example: suppose we need to round off 176 
Ten’s digit of 176 is 7 and 7 > 5
So, add 1 to hundred’s digit, which is 1 and
by adding 1 to it, we will get 1+1 = 2
And make ten’s digit and one’s digit, zero.
So, 176 rounded off to the nearest 100 = 200
And if Ten’s digit is less than 5 
then round below means make ten’s digit and one’s digit zero.
Example: suppose we need to round off 148
Ten’s digit of 148 is 4 and 4 < 5
So, make ten’s digit and one’s digit zero.
Now 148 rounded off to the nearest 100 = 100
Round Off to The nearest to Thousand: If you need to round off a number to the nearest thousand, write multiple of 1000 above (after) the number and multiple of 1000 below (before) the number and look to which Multiple, the given number is closer. Round off the number to the closest multiple.
Example: Suppose we need to round off 2176 to the nearest 1000.
Now, round off the given number to the closest multiple of 1000 (closest will be the multiple having smaller difference with the given number).
So, 2176 closest to 2000.
2176 rounded off to the nearest 1000 = 2000
Alternative method: Look at the hundred’s digit of the number we have to round off,
if Hundred’s digit is 5 or more
then round up means add 1 to thousand’s digit and make hundred’s digit, ten’s digit and one’s digit zero.
Example: suppose we need to round off 2776 
Hundred’s digit of 2776 is 7 and 7 > 5
So, add 1 to thousand’s digit, which is 2 and
by adding 1 to it, we will get 2+1 = 3
and make hundred’s digit, ten’s digit and one’s digit zero.
So, 2776 rounded off to the nearest 1000 = 3000
And if Hundred’s digit is less than 5 then round below means make hundred’s digit, ten’s digit and one’s digit zero. 
Example: suppose we need to round off 2174
Hundred’s digit of 2174 is 1 and 1 < 5
So, make hundred’s digit, ten’s digit and one’s digit zero.
Now 2174 rounded off to the nearest 1000 = 2000