Could someone give and explain to me how to multiply a Whole number by a fraction?

Question

Since 5th grade(last year) to now I still have problems doing something with fractions. I know how to add and stuff. And subtract fractions. But when it comes time to do a problem with a mixed fraction or something I have issues. So could someone give me an example and explain how to do the problem. And then give me another one to see If I get it. Please? Thank you.

Answer 1

Here's how I teach it.

 

Suppose you are told to multiply 4 x 2/3. Say it out loud, "4 times two thirds."

 

"Thirds" are just like other things--zebras, cookies, pickles.

 

So if it said "4 times two pickles," you know you would have 8 pickles.

 

so "4 times two thirds" gives you eight thirds-- 8/3.

 

Now, that's an improper fraction, which means it's greater than a whole. So you have to turn it into a mixed number:

 

Draw a box and divide it into 3rds. You now have 3/3. Draw another box, and divide it into 3/3 also--you now have 6/3. Draw one more box and divided it into 3rds. You now have a total of 9/3, right? 

 

But you only want 8/3. So shade in the 3/3 in the firsts box, 3/3 in the second box, and 2 out of 3 in the third box. You've shaded in 2 whole boxes and 2/3 of another.

 

Which means you've proven that 8/3 = 2 2/3.

 

Try the whole process yourself: what is 2 x 3/4?

 

Once you get it, practice it a lot--make up a bunch of questions and solve them. ALWAYS draw boxes, or circles, or SOMETHING visual to help, until you feel totally comfortable!

 

Cheers,

 

Matt