# fractions

• Dec 8th 2009, 06:32 AM
andyboy179
fractions
hi this is my question:

$\displaystyle 4\frac{4}{21}$ X 4

could someone explain how i would do this?
• Dec 8th 2009, 06:49 AM
e^(i*pi)
Quote:

Originally Posted by andyboy179
hi this is my question:

$\displaystyle 4\frac{4}{21}$ X 4

could someone explain how i would do this?

Treat 4 as 4/1. When multiplying fractions multiply both top and bottom: $\displaystyle \frac{a}{c} \cdot \frac{b}{d} = \frac{ab}{cd}$

Also do you mean $\displaystyle 4+\frac{4}{21} or 4 \times \frac{4}{21}$ in the first term? I will guess the former

$\displaystyle 4(4+\frac{4}{21}) = 16 + \frac{16}{21} = \frac{16 \cdot 21 + 16}{21} = \frac{352}{21}$
• Dec 8th 2009, 06:59 AM
andyboy179
Quote:

Originally Posted by e^(i*pi)
Treat 4 as 4/1. When multiplying fractions multiply both top and bottom: $\displaystyle \frac{a}{c} \cdot \frac{b}{d} = \frac{ab}{cd}$

Also do you mean $\displaystyle 4+\frac{4}{21} or 4 \times \frac{4}{21}$ in the first term? I will guess the former

$\displaystyle 4(4+\frac{4}{21}) = 16 + \frac{16}{21} = \frac{16 \cdot 21 + 16}{21} = \frac{352}{21}$

i don't understand!!!!
• Dec 8th 2009, 07:18 AM
andyboy179
i get it now! thanks!