Video Transcript
85 subtract four equals
what?
In this question, we’re
starting off with a two-digit number and we’re subtracting a one-digit number
from it. And we can use what we know
about place value to help. We can think about the tens and
the ones in our numbers. We know that 85 has eight 10s
and five ones. And the number that we’re
subtracting, four, is a one-digit number. There are some ones, but there
are no tens at all. And because we’ve already split
up our two-digit number into its tens and ones, we can start by subtracting the
ones: five ones take away four ones.
We know that five take away
four equals one. And so five ones subtract four
ones equals one one. We also know that because we’re
subtracting a one-digit number, there aren’t any tens to take away. We started with 85, and we
found the answer by simply subtracting four ones. 85 take away four equals
81.
