Can someone teach me how to figure this out?

It took 4 cups of flour to make 6 loaves. How many loaves can be made with 84 cups?

$\begin{array}{rcll} \dfrac{4\ \text{cups of flour}} {6\ \text{loaves} } \cdot x &=& 84\ \text{cups of flour} \\\\ x &=& 84\ \text{cups of flour} \cdot \dfrac {6\ \text{loaves} } {4\ \text{cups of flour}} \\\\ x &=& 84 \cdot \dfrac {6\ \text{loaves} } {4} \\\\ x &=& \dfrac{84}{4} \cdot 6\ \text{loaves} \\\\ x &=& 21 \cdot 6\ \text{loaves} \\\\ x &=& 126\ \text{loaves} \end{array}$

With 84 cups of flour can be made 126 loaves.

Think about this........84 cups / 4cups = 21 times as many

So.......we should be able to make 21 times as many loaves with 84 cups as with 4 cups.......so

21 * 6    = 126 loaves  can be made