## Friday, May 15, 2015

### Math problems of the week: Common Core-inspired math vs. Singapore Math

I. The final problem in the Common Core-inspired Engage NY 5th grade Fractions module:

1. Lila collected the honey from 3 of her beehives. From the first hive she collected 2/3 gallon of honey. The last two hives yielded 1/4 gallon each.

a. How many gallons of honey did Lila collect in all? Draw a diagram to support your answer.

b. After using some of the honey she collected for baking, Lila found that she only had 3/4 gallon of honey left. How much honey did she use for baking? Support your answer using a diagram, numbers, and words.

c. With the remaining 3/4 gallon of honey, Lila decided to bake some loaves of bread and several batches of cookies for her school bake sale. The bread needed 1/6 gallon of honey and the cookies needed 1/4 gallon. How much honey was left over? Support your answer using a diagram, numbers, and words.

d. Lila decided to make more baked goods for the bake sale. She used 1/8 lb less flour to make bread than to make cookies. She used 1/4 lb more flour to make cookies than to make brownies. If she used 1/2 lb of flour to make the bread, how much flour did she use to make the brownies? Explain your answer using a diagram, numbers, and words.

II. The last two fractions problems in the 5th grade Singapore Math Primary Mathematics 5A Workbook (in Unit 4, Multiply and Divide Fractions, pp. 98-99):

3. After giving 1/3 of his money to his wife and 1/4 of it to his mother, Mr. Li still had \$600 left. How much money did he give to his mother?

4. Lucy spent 3/5 of her money on a purse. She spent the remainder on 3 T-shirts which cost \$4 each. How much did the purse cost?

III. Extra Credit

One of the biggest challenges found in Singapore Math problems (and not just in the one that recently went viral) is in figuring out what the first step is.

Compare the obviousness of the first steps in the EngageNY problems to those of the Singapore Math problems above.

Anonymous said...

Are you sure the first set of questions was on fraction? It seems to be all addition and subtraction to me.

Katharine Beals said...

Thanks for noticing this! The fraction bar did not go through in the formatting. I've just added it where it was missing.

kcab said...

LOL, and here I was thinking about how industrious Lila must be, baking in such large quantities.

Anonymous said...

The new problems are much wordier and demand wordier answers. Are they trying to disfavor boys, AS kids and ELL?

Anonymous said...

I found that drawing diagrams for the CC problems was far more cumbersome that simply working them numerically because conceptually they were very straightforward. Not so with the Singapore problems which are not straightforward at all unless you draw a diagram.

Why couldn't the US simply adopt Primary Mathematics as the "standard" and be done with it?

Barry Garelick said...

The new problems are much wordier and demand wordier answers. Are they trying to disfavor boys, AS kids and ELL?

Katharine and I have addressed the issue of requiring students to "explain their answers" rather than simply showing their work in an article at Ed News.

S Goya said...

Actually, I use a combo method for showing work wherein for each step the student identifies the property that allowed them to take the step. Sometimes the rationale is merely "math fact." However, pictures are also a great way to show work and understanding. As usual, it is not an either/or issue. As usual, the efficacy depends on a skilled teacher. Sometimes, I think Katherine is spends too much time creating unnecessary polarization. I do understand the temptation to do so.