Fraction of a Group (Part 2)
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Your child should understand the basics of what a fraction is before starting this section.
Review:
In this section we look at how to apply fractions to a large group of objects. There are a few ways to explain this. The first way is to draw it out as an array. This method can be used if your child has not yet learned about equivalent fractions or division.
Drawing It Out
Draw out using simple shapes like circles to represent the group of items. Draw it out in an array where the number of circles in each row is the same as the denominator of the fraction.
Question: I bought 8 balloons for a party. One-quarter of my balloons are red. How many red balloons did I buy?
Work it out:
One-quarter means one part out of four parts. The denominator is 4 so have your child draw 2 rows of 4 circles to represent the 8 balloons.
Since one-quarter means one out of four, have your child write the letter R for Red in one of the circles of each row.
Your child can now see that the one-quarter is applied to each row.
So now it is easy to see that one-quarter of 8 gives the answer 2.
This means that out of 8 balloons, 2 of them are red.
This method is very easy for your child to understand the concept of fraction of a group. The limitation of this method is that the numbers used are usually quite small. If your child has difficulty learning about equivalent fractions, come back to this method.
Draw it Out Part 2
This is similar to drawing it out, but it does not have to be neatly drawn in an array.
Question: I have 12 star stickers. I gave away one-third of my stickers. How many stickers did I give away?
Work it out:
Draw the stars a little randomly.
One-third means one out of three. So make groups of three. Shade or colour one star in each group of three to represent the sticker that is given away.
The answer is: I gave away 4 star stickers.
You can also ask your child "How many stars stickers are left?"
Draw it Out Part 3
Another way to draw it out is by drawing in groups right from the beginning. We usually draw rectangles cut into the same number of parts (boxes) as the denominator.
Question: I have 30 books. I gave away two-fifths of them. How many books did I give away?
Work it Out:
Draw a large rectangle and divide it into 5 parts. Ask your child how many books will each part have? If your child is not used to division, ask him or her to draw one book in each box till there is a total of 30 books.
Now colour or shade 2 of the boxes.
Two-fifths of 30 is 12.
The answer is: I gave away 12 books.
Drawing Models
Now your child is ready to draw models using numbers. This method can be used for any type of number whether it is whole numbers, fractions or decimals. By this stage your child should know how to use division.
Most students from the 3rd grade on will be able to understand how to draw models.
Question: I have 18 beads. One-third of them are black and remainder are red. How many red beads do I have?
Work it out:
First draw the rectangle cut into 3 equal parts and write the number 18 as shown in the diagram.
Next, ask your child to figure out the number that goes into each box and write it in. The working should be 18 divided by 3.
The last step is to shade one-third.
The model shows 6 black beads and 12 red beads.
Here are some worksheets for more practice.