Rounding off is one of the most used techniques i the the world. for estimation in the exams of college to buying vegetables from the vendors. we can basically round of numbers to one decimal place, two decimal places, three decimal places, significant figures, tens, hundreds, thousand, and many more. But in this time we will discuss about rounding of to the nearest tens. for example you have the number 275 and you have to round it of to the nearest tens. you fist check out the number in its units. if it is 0 then no need to round off. if i extends from 1-4 then it will be rounded off to its nearest tens that is 270. when it extends from 5-9 then it is rounded off to the next tens that is 280.so this is how simple rounding off is.