# Thread: Dividing fractions

1. ## Dividing fractions

Im working through a book "Maths for Science" and here is another example I dont understand:

For example, $\displaystyle 5/15$ can be simplified by dividing the numerator
and denominator by 3 to get $\displaystyle 1/3$

This is what I dont understand how can the numerator be divided by 3? 5 divided by 3 is 1.666666667 on my calculator!

Although I instantly know $\displaystyle 5/15$ is also $\displaystyle 1/3$ in my mind.

$ilver 2. Originally Posted by$ilver
Im working through a book "Maths for Science" and here is another example I dont understand:

For example, $\displaystyle 5/15$ can be simplified by dividing the numerator
and denominator by 3 to get $\displaystyle 1/3$ Mr F says: The red 3 should be a 5 (since 5 is the common factor of 5 and 15).

This is what I dont understand how can the numerator be divided by 3? 5 divided by 3 is 1.666666667 on my calculator!

Although I instantly know $\displaystyle 5/15$ is also $\displaystyle 1/3$ in my mind.

$ilver .. 3. Hello ! No, they divided the numerator and denominator by 5. See :$\displaystyle \frac 5{15}=\frac{{\color{red}5} \times 1}{{\color{red}5} \times 3}$So this can be simplified :$\displaystyle \frac{5 \times 1}{5 \times 3}=\frac 55 \times \frac 13=1 \times \frac 13$and gives the result ^^ 4. lol thanks guys no wonder I was confused! Its a typing error then$ilver