Video Transcript
We can think about place value to
help us subtract. Pick the correct way to decompose
58 into tens and ones. Subtract 26 from 58 by taking away
six ones and then two 10s.
In this question, we have to
subtract 26 from 58. And we’ve been given some models to
help us. When we’re subtracting a two-digit
number like 26 from another two-digit number like 58, it helps if we start by
modeling the number we’re taking away from. In this case, we need to model the
number 58. Only one of our models is
correct. How could we decompose or break
apart the number 58 into tens and ones correctly? It must be the second model. It has a five in the tens place and
an eight in the ones place. The model shows five 10s, 10, 20,
30, 40, 50, and eight ones. So this is the correct way to
decompose 58 into tens and ones.
We can also use this model to help
us subtract. We’ve modeled the number we’re
taking away from, which is 58. Now we can subtract 26. We always start by subtracting the
ones first. We have eight ones in the number
58, and we need to subtract six. Eight ones take away six ones
leaves us with two ones. Next, we need to subtract the
tens. We know the number 58 has five
10s. And we need to subtract two
10s. The number 26 has two 10s. We had five 10s. We’ve subtracted two 10s. We have three 10s left. 58 subtract 26 equals 32.
When we’re subtracting a two-digit
number from a two-digit number, the first step we can do is to model the number
we’re subtracting from. This is the correct model to show
the number 58. When we’re subtracting a two-digit
number from a two-digit number, we always start by subtracting the ones first. Then we subtract the tens. 58 subtract 26 equals 32. We used our knowledge of place
value to help us subtract.
