Fast Fractions

In an earlier post, I talked about fast math. We used the difference from 10 or 100 to multiply larger numbers quickly. We can also talk about fast fractions…

Adding fractions that do not have a common denominator is not always easy. Traditionally, we are tasked with finding the LCD and then we convert both fractions to equivalent fractions with that LCD and FINALLY, we can add them. Fast Fractions takes out a step and a half.

Let’s start with 2/3 + 3/5.

Multiply the denominator of the first fraction by the numerator of the second, then do the same with the denominator of the second and the numerator of the first. Multiply both of the denominators.

2       ₊    3   =        (5 x 2) + (3 x 3)   =    10+9  =   19

3             5                        15                     15         15

(I apologize for the sloppy fractions…I couldn’t get them to display vertically any other way.)

Simplify your answer, if needed, and Viola! You have added your fractions.

Myths

I was recently reading an alumni magazine when I came across an article by a professor that was enumerating the common math myths and I thought it would be good to pass along…

Myth 1 – Men are better at math than women

There has been no research that proves this to be true. It is true that the mathematical sciences are filled with men, no question. The real question is why aren’t there more women there? There are so many theories out there; Nature vs. Nurture, The math classes are boy centric, the list goes on. The bottom line is: get the girls out there!

Myth 2 – Math is not creative

Math IS creative. You need to have a creative, problem solving mind to attack a lot of the math problems you encounter in the real world.

Myth 3 - There is one way to solve a problem.

There is no one “right way” to solve any problem, there are multiple ways to get the right answer. Think about planning a party, there are many ways to decide how much cake everyone will get.

Myth 4 –  You need to memorize a lot of facts, rules and formulas to be good at math.

Memorization is not nearly as effective as understanding the concepts. Think about the multiplication facts that most of us memorized as kids. We know from memorization that 4x4 is 16, but we also know conceptually that his also represents 4 groups of 4.

Polly Gone Crackers

So, you need to remember all of the polygon prefixes by 8 AM tomorrow, but you can’t remember the difference between a pentagon and a heptagon. Bummer.  What’s a kid to do? Have you tried MNEMONICS? No, not Satan worship…that another blog all together! I am talking using a form of word association to connect those pesky prefixes to the numbers they represent.  Most students will know how many sides a TRIangle has. But how many sides does a nonagon have? The nonagon has NINE sides. To help you remember that Nona means nine, make up a story about nona…Nona could be your crazy Aunt Nona who has nine fingers or, you could use the fact that Nona and Nine both start with N. The point is, find a story that you can remember that will firmly associate the prefix and the number.

Here are some of my favorite associations if you get stuck….

Triangle : Tri=3 : Tricycle, Trident has 3 points (think Little Mermaid)

Quadrangle: Quad=4: Quad at a school has 4 walls, there is an ATV called a Quad with 4 wheels.

Pentagon: Penta=5: There are 5 letters in Penta, there are 5 points on a star named Penta.

Hexagon: Hex=6:  SIX and HEX both end in X, both have 3 letters

Heptagon: Hepta=7:

Octagon: Oct=8 – octopus…

Nonagon: Nona=9: see story above

Decagon: Deca=10 : a ‘deck of’ 10 cards

Undecagon: Undeca=11: Think UN is like 1 and DECA is 10 so  10+1=11

Dodecagon: Dodeca=12:  DOS (Spanish 2) + DECA (10)=12

Money Makes the World Go 'round (Part 2)

For the middle schoolers and high schoolers everywhere. Cell phone roulette....

Did you know that, according to GeekSugar.com, teens are typically sending around 3000 texts per month?!! This frightens me. It should frighten everyone.

We've all heard the cries of our teens.."But MOM, everyone else has a cell phone, I HAVE to have one now!" Granted, the social stigma of tecnological inferiority is daunting, but those crazy kids have no idea what it means to a household budget! There are so many plans out there, all claiming the best service and the lowest prices.  If your kid is clamoring to raise thire social status with a new smartphone, have them do the math. Start by having them research phone plans.  Use the rate of 3000 texts per month as a baseline. Don't forget to have them look at the talk time.... Have them poll friends on their talk time usage. (You should poll your friends too on the kids usage in other households…) Every house has their own budget, adn the student needs to find a plan that will fit in without taking food off of the table for everyone else.