PARENT TO PARENT

A: Fractions are actually quite simple, if you know one little secret. The question is, "What is a fraction?" There are lots of ways to answer, but ultimately, a fraction is a division problem - nothing more, nothing less. This is a very powerful concept. If your daughter can do long division and knows how to divide out a remainder into decimal form, she can convert fractions.

First, review long division with your daughter, and make sure she doesn't just quit and put the remainder next to her answer with an 'r' in front of it. I am continually amazed at how many children make it all the way to high school without learning how to finish a division problem. For example, divide 19 by 4. Your daughter should be able to set up a long division problem and get 4.75 for an answer, not 4 r3. Now just apply long division to the fraction.

For example, to convert 3/4 to a decimal, read the fraction, from the top down, as a division problem, "three divided by four". Set this up with long division, and you will find that the quotient is .75 - the decimal. That's it.

There are a couple ways to convert a fraction to a percent. One technique taught in many classrooms is to set the fraction equal to x over 100 (x/100), cross multiply and solve for x. This is fine for older students, but often confuses younger ones, since the algorithm involves algebraic theory. Since your daughter has just learned to convert a fraction to a decimal by dividing, the easiest thing to do is, move the decimal point two spaces and write a % sign.

When I was young, I could never remember which way to move the decimal when converting from a decimal to a percent or from a percent to a decimal. I tell my students to move the decimal two spaces toward the percent sign when you put it down, and away from the percent sign when you take it away. I think of the percent sign as "attracting the decimal", like a magnet. For example, to convert .36 to a percent, move the decimal two points to the right (toward the % sign), and you have 36%. To convert 57% to a decimal, move the decimal to the left (away from the % sign) and you have .57. Notice that there is no decimal in 57%. Be sure to take a moment and remind your daughter that, although it is not written, a whole number can be expressed with a decimal at the end.

Another detail to check is that she is moving the decimal only two spaces. For example, 238% = 2.38, not .238. Many students inadvertently put the decimal at the beginning of the digits without counting over the two spaces.

Don't forget to practice this with numbers that have one, three, or more digits; also practice with whole numbers larger than 100. Here are some examples: 3% = .03 (the zero is added so you can move the decimal two places). .9 = 90% (again, a zero is added so you can move the decimal two places). .0026 = .26% (notice the decimal in front of the % - this is less than one percent, and is a legitimate number).

There are techniques to convert a fraction directly to a percent. I generally don't bother teaching them, since a student can always divide to get a decimal, then just move the dot (but please call it a decimal).

Finally, be sure to check with your daughter's teacher. Some curricula demand that a student use a specific technique to obtain an answer, and you don't want your child getting correct answers but being marked wrong for using inappropriate techniques. If this is the case, I generally help the students make the relationship between the classroom technique and the ones I've discussed here. I then remind them that they can always use the classroom algorithm on their paper, then check their work using the simpler division techniques, to make sure they've gotten the correct answer.

I also remind them to never argue with the teacher. First of all, it is rude. Secondly, it won't help. And finally, the difficulties many children face in math often stem from the textbooks, not the teachers.

I hope this helps, Michele

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