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## Topic D: Fraction addition and subtraction

Current time:0:00Total duration:1:45

## Video transcript

A common house
spider has 8 eyes. If a spider is looking at
you with its 2 front eyes and 3 of its other eyes,
what fraction of its eyes are looking at you? And just to show that we're
not making this stuff up, this is actually
pictures of spiders. And you see in every
one of these pictures they have eight eyes, even
this one's got other eyes right over here-- 1,
2, 3, 4, 5, 6, 7, 8. I never even realized this. This is actually quite creepy. But anyway, let's actually
focus on the problem. So it's looking at you
with 2 of its 8 eyes. So the 2 front eyes represent
what fraction of the eyes? Well, it represents
2 of the 8 eyes. You could look at
it right over here. You have 8 eyes. We have the 2 front eyes. That's 1 and 2 of the 8. And it says it's also looking
at us with 3 of its other eyes. So it's also looking at
us with 3 of the 8 eyes. And so you can
imagine that might be that one, that
one, and that one. So this is really
about adding fractions. This is about adding 2/8 of
something to 3/8 of something. So what fraction of its
eyes are looking at us? Well, it's still going
to be a fraction of 8. It's going to be still out
of 8-- 2 plus 3 over 8, which is just going to be
equal to 5/8 of the eyes. 5 out of the 8 eyes
are looking at us. And we see it right over
here-- 1, 2, 3, 4, 5. 5 of the total of 8
eyes are looking at us in a fairly creepy way.