English for Mathematics

1. FRACTIONS
Addition of Fractions
You have to remember just one think. The denominator always must be the same. Let’s
take a circle for our example. Take a circle with five pieces. Each piece is one over five of
the circle. And two pieces will be two over five of the circle. Let’s add one over five and
two over five. one over five plus two over five is equal two one plus three over five equals
three over five.
Let’s look at one more example. Take a watermelon for our example. Take a watermelon
with eight pieces. One piece is one over eight of the watermelon and three pieces is three
over eight. Let’s add of the two. One over eight plus three over eight is equal to one plus
three over eight equals four over eight. If we reduce four over eight, we get a half.
Now let’s do one without pictures. One over five plus three over five. Since the
denominators are the same, we can simply add the numerator. Therefore, we have the
numerator as one plus three and the denominator remains five. We get four over five. So,
one over five plus three over five equals four over five.
Now, let’s try and add two fraction which have different denominators. Let’s add a half
and one over five. We can add the numerator only if the denominators are the same. So
how do we make the denominators same? The LCM of two and five is ten. So ten, which is
the LCM, is our new denominator. Change the first number, a half, so that is has ten as
the denominator and change the second number, one over five, so that is has ten as the
denominator.
Ten divide two is equal to five. Then five times one equals five. Ten divide five equals
two, the two times one is equal to two. So, five over ten plus two over ten equals seven
over ten. So, a half plus one over five equals seven over ten.