Fractions

  • Fractions are a way to measure equal parts of something, like time, money, or weight or anything that has a unit measure. Half an hour, half a dollar, quarter past, half a cup of flour and so forth are a part of most people's lives. Here is a quick and dirty look at fractions, which are written with one number above a small line and one number below it. Unfortunately, I don't know how to make the computer do that. One half would appear with a 1 directly above the little line and then a 2 would be right under that. On a computer it will look like this, 1/2, until I can figure out how to do it better.

    The top number is called the numerator, while the bottom number is the denominator. The numerator tells how many parts you're talking about or looking at, while the bottom or denominator, tells how many parts make up a whole unit. The fraction 5/9 tells us that we are looking at five equal parts and that there are nine equal parts in the whole group. Read the top number, numerator, as it is, five, and the bottom number, the denominator, like ninths.

    To compare and order fractions there are a few things to remember. • If the fractions have the same denominator, simply compare the numerator. 3/8 and 5/8 have the same denominator, so looking at the numerators shows that 3 is less than 5 so 3/8 is less than 5/8. Math folks write, "3/8 < 5/8". If the numerators are the same then whichever denominator is smaller (meaning the piece size is bigger) is the larger fraction. For example, 3/4 and 3/8 have the same numerator of 3 and the denominators are different. If two equal size cakes are baked and one is cut into 4 equal pieces and your dog eats 3 pieces of it, while the identical cake is cut into 8 equal pieces and your kangaroo eats 3 of them, it is easy to see that your dog ate 3 pieces that were much larger than the pieces your kangaroo ate, so 3/4 is greater than 3/8, even though instinct tells us 8 is bigger than 4, it is opposite in fractions as you can see.

    Equivalent fractions *** huge concept*** when the numerator and denominator are the same you have 1 whole, like four quarters equal 1 whole dollar. When you multiply or divide anything by one, you don't change the outcome. Now replace the 1 with 2/2 or 3/3 or 4/4 or 5/5 or 6/6 or 7/7 and so on. Equivalent fractions are created by multiplying or dividing straight across by the same number top and bottom. For instance, take 1/2 or one half and multiply by 2, top and bottom. 1 X 2 = 2 on top, while 2 X 2 = 4 on bottom so 1/2 = 2/4. Find an equivalent fraction for 5/6. Multiply top and bottom by 3 and get 15/18. This is a key concept.