Video Transcript
Daniel needed some school
supplies. He used tally marks to record his
requirements. Which of the following bar graphs
represents the tally chart?
This problem tells us about someone
who needs some supplies for school. And we’re told that he used tally
marks to record what he wanted. And we’ve shown these tally marks
in a tally chart. Do you remember how tally marks
work? Each mark represents one more. And in this case, it’s one more
object that Daniel needs. Instead of recalling them like
this, where we have lots and lots of individual marks, it can be very difficult to
count them; we’d be counting each one separately. Instead, what we do is as soon as
we get to a multiple of five, one, two, three, four, and then the fifth one, we make
into a block of five. So we have six, seven, eight, nine,
10. And so, by recording tally marks in
blocks of five, it makes it much easier to count.
Let’s start then by counting how
many of each type of supply Daniel needs. Firstly, the notebooks. We can see one group of five and
then two more tally marks. And five plus two more is —
seven. The next box we can see how many
pens Daniel needs. And there are two groups of five
tally marks, so that makes 10 pens. Next, we’ve got an eraser or a
rubber. And we can see four individual
tally marks, so that’s four erasers that he needs. And finally, on the end, we’ve got
some backpacks. And we can see that he needs two
backpacks, probably to told all this equipment in.
Next, we’re shown two bar
graphs. And we’re asked which of the
following bar graphs represents the tally chart. In other words, which one shows
that Daniel is going to need seven notebooks, 10 pens, four erasers, and two
backpacks? Let’s read them to find out. We’ll start by looking at the first
bar graph. And we could look at the first bar
on it, which we can see represents the number of notebooks that Daniel needs. If we put our finger on the very
top of this bar and draw a line all the way across to the side, we can see that it
reaches the number six. We can tell by the label that this
represents the number of supplies Daniel needs. This bar graph tells us that Daniel
needs six notebooks. But this is wrong, isn’t it? We know Daniel needs seven
notebooks.
Let’s check the second bar graph
and see if this is any better. And again, if we go to the top of
the first bar and read across, this time we can see the correct answer. Daniel is going to need seven
notepads. It looks like our second bar graph
is correct, but let’s just read the other bars. They tell us that Daniel is going
to need 10 pens, which is correct. He’s going to need four erasers,
which is also correct. And if we look at the height of the
final bar, we can see that he’s going to need two backpacks. Although the tally chart in the bar
graph are two different sorts of things, they both show the same information and the
bar graph that represents a tally chart is the one that shows that Daniel needs
seven notebooks, 10 pens, four erasers, and two backpacks.
