Wednesday, April 4, 2012
Standing Fractions on Their Heads
This weekend my husband was taking one of those intelligence tests online. He was reading them out loud to us to find out how he had gone wrong. The questions were basically those trick jokes you hear at parties...like 100 people got on the bus, 50 people got off the bus, 25 people got on the bus (etc)--what color were the bus driver's eyes?
Anyway, one did require MATH. It asked the question, "What is 30 divided by 1/2 plus 10?"
Even my son the grad school architect had trouble with this one. Try it first before you see how one of my former blogs on fractions works here.
The answer is NOT 30/2 (15) plus 10 = 25. (It didn't say IN half).
The equation is (30 -:- 1/2) + 10.
Whenever multiplying by a fraction, make it stand on its head. Turn it upside down.
So 30 x 2= 60 Order of operations tells you to do what's in the parenthesis first.
60 + 10 = 70. That's the answer.
I LOVE standing fractions on their heads. It helps get those pesky things out of equations.