Answer:
examine the next digit and increase the number accordingly, before dropping the digits of no interest.
Step-by-step explanation:
You round any number by looking at the digit in the place to the right of the one you want to round to. If it is 5 or more, you add 1 to the number in the place you're rounding to, and drop (or zero) all digits to the right of that.
If you want to round this to tenths, you observe that the hundredths digit is 7, which is more than 4. So you add 1 tenth and drop the hundredths digit:
99.87 ≈ 99.9 . . . . rounded to tenths
If you want to round this to units, you observe that the tenths digit is 8, which is more than 4. So you add 1 unit and drop the tenths and hundredths digits.
99.86 ≈ 100 . . . . . rounded to nearest integer
