WEBVTT
Kind: captions
Language: en-GB
00:00:01.350 --> 00:00:08.360
Han and Samir had $680 altogether. Han had
three times as much money as Samir. If Han
00:00:08.360 --> 00:00:16.630
spent $135 of his money, how much did he have
left? So the bar model can help us visualise
00:00:16.630 --> 00:00:22.180
quite nicely the relationships between the
different amounts on the basis of the information
00:00:22.180 --> 00:00:32.160
that we have from this problem. So if, say,
Samir has this amount of money, we know that
00:00:32.160 --> 00:00:47.420
Han had three times as much. So if this is
how much Samir has then this is how much Han
00:00:47.420 --> 00:00:57.820
has. And we know that altogether they have
£680. Now one important piece of understanding
00:00:57.820 --> 00:01:04.860
to have while using the bar model is that
each of the boxes represents an equal amount,
00:01:04.860 --> 00:01:13.869
so, if we divide 680 by 4 we should be able
to find how much each of the boxes represents.
00:01:13.869 --> 00:01:30.270
So I’m going to do 680 divided by 4: 4 goes
into 6 one time. 1 x 4 = 4. 6 - 4 is 2 and
00:01:30.270 --> 00:01:39.109
I’m going to bring the 8 down. 4 goes into
28 seven times. 7 x 4 is 28. I’m going bring
00:01:39.109 --> 00:01:52.009
the zero down and 4 goes into 0 zero times.
So 170. So now I know that each of these boxes
00:01:52.009 --> 00:02:02.799
represents $170 and I know that Samir has
$170 dollars, and to find out the total amount
00:02:02.799 --> 00:02:19.010
of money that Han has, I need to multiply
170 by 3. 3 x 0 is 0. 3 x 7 is 21. 1 x 3 is
00:02:19.010 --> 00:02:30.930
3, add the 2 = 5. So I know that Han has $510.
Now the problem asks, if Han spent $135 of
00:02:30.930 --> 00:02:39.120
his money, how much did he have left? So all
I need to do now is the subtraction 510 – 135:
00:02:39.120 --> 00:02:51.470
0 – 5: I can’t do that so I’m going
to borrow 1 from there and be left with 0
00:02:51.470 --> 00:03:01.160
there. 10 – 5 is 5. 0 – 3: I can’t do
that so I’m going to borrow from there.
00:03:01.160 --> 00:03:14.610
10 - 3 is 7. 4 - 1 is 3. 375 is the answer
to my question.