Video Transcript
You can use a number line to
subtract. Take away ones by counting back in
ones. 56, 55, 54, 53, 52. 56 subtract four equals 52. Take away 10s by counting back in
10s. 82, 72, 62, 52. 82 subtract 30 equals 52. Use number lines to find these
differences. 43 subtract six equals what. 54 subtract 40 equals what.
We’re shown two calculations and
two number lines. We’re asked to use the number lines
to help us find the difference. First, we have to find the
difference between 43 and six. In other words, we have to subtract
six from 43. The number 43 is already marked on
the number line. To subtract six, we need to count
back six. And we need to count back in
ones. 43, 42, 41, 40, 39, 38, 37. We started at 43, and we counted
back six on the number line. 43, 42, 41, 40, 39, 38, 37. 43 subtract six is 37.
Next, we have to use the number
line given to find 54 take away 40. The number 54 has two digits. The five digit is worth five
10s. We have to subtract 40. We know that 40 is four 10s, so we
have to subtract four 10s from 54. Let’s use the number line to
help. 54 subtract 10 is 44. 44 subtract 10 is 34. 34 take away 10 is 24. 24 take away 10 is 14. We started at 54 and counted back
four 10s. 44, 34, 24, 14 because 40 has four
10s.
We used number lines to find the
differences. To find 43 take away six, to find
43 take away six, we started at 43 and counted back six ones. 43 take away six is 37. And to find 54 subtract 40, we
started at 54 and counted back four 10s. 54 subtract 40 is 14.
