Friday, July 27, 2012

Math problems of the week: 4th grade Investigations vs. Singapore Math

I. The rounding numbers assignment of the 4th Grade TERC/Investigations Student Activities Book (Unit 5, "Landmarks and Large Numbers," p. 43):

II. The rounding numbers assignment of the 4th grade Singapore Math Primary Mathematics 4B Workbook (Unit 1, "Whole Numbers," pp. 19-20):


Dawn Hargett said...

I wish someone in the educational field could explain to me and convince me of the need for the skill of rounding to the first digit. Nothing frustrates me more than this worthless skill! And, no one has been able to reasonably answer why it is a useful skill. Our son's curriculum teaches it with no "why" they will need to know it. We can come up lots of reasons for it's uselessness, however!

Auntie Ann said...
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Auntie Ann said...

I just looked through the "Math Journals" for EM's 5th grade curriculum. I looked for fraction addition and subtraction problems which required finding a common denominator. I found only 65 of them in the entire year's worth of journal. And 5th is supposed to be the year that really nails down fractions.

There were places where students had to find the common denominator for two fractions, but nothing else. There were places where diagrams spelled out exactly what the kids were supposed to do, so all they had to do was count squares. There were places where kids were told to use a calculator to add fractions, and even a page where kids were supposed to use a slide rule to add fractions.

But for problems requiring multi-step fraction add/sub (ie. find the common denominator, change each fraction into one with that denominator, do the addition, then reduce the fraction to its simplest proper form): just 65 of them.

In addition nearly all of them were very simple, with denominators like: 2 & 4, 4 & 8, 3 & 6, etc. Absolutely none had a denominator larger than 10.


I assigned our 10-year-old boy a page of 40 to do yesterday, and moved on to do both multiplication and division today. He got the idea of a reciprocal quickly, and loved the idea that dividing one-half, was the same as multiplying by 2. I don't believe EM ever deals with the concept of a reciprocal, thinking it's too hard for the poor wee little things to understand.

Unfortunately, he's stuck in 5th grade EM next year with no chance to do anything else, except at home after school.