Omar bought 7 and1/2 pounds of ground beef for a family cookout. How many 1/4-pound burgers can he make from the ground beef?

Let's start out by turning 7 and 1/2 into a improper fraction.

This would be 15/2. To do this, I multiplied 7 times 2, then added 1 to it. Then I put this number over 2. This is how you would turn a mixed fraction into an improper fraction. Here's a chart showing what a mixed fraction and improper fractions are:

Now that we have 15/2, we want to divide this by 1/4 to see how many 1/4-pound burgers he can make from the total ground beef he bought.

When you divide two numbers, you multiply by the recriprical. That's a pretty big word, but it just means flip-flop the second fraction.

So, 15/2 ÷ 1/4 is really

$${\frac{{\mathtt{15}}}{{\mathtt{2}}}}{\mathtt{\,\times\,}}\left({\frac{{\mathtt{4}}}{{\mathtt{1}}}}\right)$$

Now we just multiply the two fractions:

$${\frac{{\mathtt{60}}}{{\mathtt{2}}}}$$

And 60/2 is really just 30.

Omar can make 30 1/4-pound burgers out of 7 and 1/2 pounds of ground beef!