Video Transcript
Subtracting Two-Digit Numbers
without Regrouping
In this video, we will learn how to
subtract a two-digit number from a two-digit number without crossing a 10 and model
this with place value equipment. Here’s a two-digit number, 67. And we have to subtract another
two-digit number, 53. The first thing we need to do is to
model the number we’re subtracting from. The number 67 has six 10s and seven
ones. Our second step is to subtract the
ones. When we’re subtracting a two-digit
number from a two-digit number, we always subtract the ones first.
We’re subtracting 53 from 67. And the number 53 has three
ones. So let’s subtract three ones from
our seven ones. One, two, three. Seven take away three leaves us
with four ones. Our final step is to subtract the
tens. We know that 67 has six 10s, and we
have to subtract five 10s because the number 53 has five 10s. One, two, three, four, five. Six 10s take away five 10s leaves
us with one 10. 67 subtract 53 equals 14.
Let’s recap what we’ve learned so
far. When we’re subtracting a two-digit
number from a two-digit number, first we model the number we’re subtracting
from. Next, we subtract the ones. Then we subtract the tens. Let’s practice what we’ve learned
about subtracting two-digit numbers from two-digit numbers by answering some
questions now.
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.
Find the result of the following:
96 subtract 63 equals what.
In this question, we’re subtracting
a two-digit number from a two-digit number. We can use place value equipment to
help us model the number 96 because this is the number we’re subtracting from. The number 96 can be modeled using
nine 10s and six ones. Now that we’ve modeled the number
we’re subtracting from, our next step is to subtract the ones.
We have six ones, and we need to
subtract three. One, two, three. Six take away three leaves us with
three ones. Our next step is to subtract the
tens. 96 has nine 10s, and we need to
subtract six. Nine 10s subtract six 10s leaves us
with three 10s. 96 subtract 63 equals 33.
We used our knowledge of place
value to help. First, we modeled the number we
were subtracting from. We subtracted the ones first and
then the tens. 96 subtract 63 equals 33.
24 subtract 11 equals what.
In this question, we’re subtracting
a two-digit number from a two-digit number. And we know that two-digit numbers
have a tens and a ones digit. When we’re subtracting a two-digit
number from a two-digit number, it helps if we start by modeling the number we’re
subtracting from. We’re subtracting from the number
24, which has two 10s and four ones.
Now we can start by subtracting the
ones. We know that 24 has four ones and
11 has one. So we need to subtract one from our
four ones. Four take away one leaves us with
three ones. Next, we need to subtract the
tens. 24 has two 10s, and we need to take
away one 10. One 10 take away one 10 leaves us
with one 10. 24 take away 11 equals 13.
We used our knowledge of place
value to help us subtract. First we modeled the number we were
subtracting from. Then we subtracted the ones. And finally, we subtracted the
tens. 24 subtract 11 equals 13.
What have we learned in this
video? We’ve learned how to subtract a
two-digit number from a two-digit number using place value equipment. We learned how to model the number
we’re subtracting from. We also learned that first we
subtract the ones and then we subtract the tens.
