Social Question
What do you think of this Singapore math problem?
Students from Singapore get the highest scores in international math tests. The claim is that this is largely due to a technique that they use before teaching algebra known as block modeling. I have been looking at several examples online. The problems are easy to solve algebraically, but I am having a hard time using block modeling.
Here is an example of a 7th grade math problem. 3/5 of the men at a conference are from Georgia and ⅓ of the women are from Georgia. The number of men from Georgia is the same as the number of women from Georgia and there are 8 more women than men. How many people are from Georgia?
You might want to pause for a moment and work this out on your own. Algebraically, I let x = number of men. Then we get:
3/5 x = ⅓(x+8).
x works out to be 10. There are 3/5x=6 men from Georgia and an equal number of women for a total of 12.
Here is the diagram used for the Singapore approach. The top row shows 3 of the 5 men boxes representing the 3/5 of the men from Georgia. Since the number of women from Georgia is the same as the number of men from there, 3 boxes also represent the number of women from Georgia.
Because ⅓ of the women are from Georgia, we use 9 boxes to represent the total number of women. The women have 4 more boxes than the men and since there are 8 more women than men, each of those boxes must stand for 2 people. There are 6 boxes representing people from Georgia, so there must be a total of 6×2=12 people from there.