Video Transcript
Which of the following numbers
rounds to 100 when rounded to the nearest hundred? 161, 176, 156, or 78.
In this question, we have to work
out which of the four numbers we’re given rounds to 100 if we round the numbers to
the nearest hundred. Let’s start with the number
161. When we’re rounding to the nearest
hundred, we need to look to the tens digit. If the tens digit is worth five or
more, we have to round up. We know that six is more than five,
so we need to round up. The number 161 has one 100. It comes between the hundreds 100
and 200. We need to round up to 200 because
161 has six 10s, and if the tens digit is five or more, we have to round up. 161 rounded to the nearest hundred
is 200.
We’re looking for numbers, when we
round them, which round to 100. The number 176 has seven 10s. Seven is more than five. So again, we need to round this
number up. 176 rounded to the nearest hundred
is 200. The number 156 has five 10s, and we
know if the tens digit is five or more, we have to round up. So 156 rounded to the nearest
hundred is also 200.
The number 78 has no hundreds. It comes between the numbers zero
and 100 on the number line. When we’re rounding to the nearest
hundred, we need to look to the tens digit which, in this case, is a seven. And we also know if the tens digit
is five or more, we need to round up. So 78 rounded to the nearest
hundred is 100. The number which rounds to 100 when
rounded to the nearest hundred is 78.
