Help with reducing fractions Singapore 4A

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We are having a bit of difficulty with reducing fractions to their simplest form in Singapore 4A.... The concept isn't well explained in the textbook or workbook, and is introduced BEFORE lowest common denominators. We are working through, and I can explain how 4/8 is the same as 1/2, but it is harder for me to explain how 3/12 is really 1/4 or similar skills. It isn't expounded on, but the answer key expects them to be able to reduce these fractions although i can't find that the skill has been taught at this point in the books. We have made it to subtracting fractions, page 48 in the textbook and 46 in the workbook. Anyone else run into this?

Thanks!!!!!

[tjneary99]

Hi there,
We have used Khan academy online for help. Have you tried that? It is a free site that is well organized by skill level and they will teach the concept briefly and kids can do practice problems. It has helped us for things like remainders, reducing fractions etc.... when we needed some extra help. Some things I find harder to teach than others--I can do it, but I cannot explain how to do it so well. Also for Singapore's word problems in the 5 and 6 levels, we buy the text and (in 6th the HIG) are able to do them as some are quite challenging if you are not a natural math person(and even if you are perhaps:O). Something to think about for future reference if you find the word problems a challenge later on. I found owning the textbook invaluable this year to helping me teach. We like Singapore a lot, but it teaches in a different way than I learned but that is a good thing-my daughter really seems to get the ''whys'' behind math better. There is also a Singapore yahoo group you can join where people post questions on different math problems etc...Hope that helps.

[StephanieU]

We don't use Singapore, but I used to teach math for elementary school teachers. Have you drawn out the problems? Make a rectangle that is 3x4 for example for the 3/12's problem. Color 3 squares (one column or row). And see if that helps explain why 3/12=1/4. If you have something like snap cubes, you could also use those instead of drawing.

[lucsch]

We don't use Singapore, but I used to teach math for elementary school teachers. Have you drawn out the problems? Make a rectangle that is 3x4 for example for the 3/12's problem. Color 3 squares (one column or row). And see if that helps explain why 3/12=1/4. If you have something like snap cubes, you could also use those instead of drawing.

We don't use Singapore, but this is exactly how I explain fractions. I draw it on our whiteboard. I usually try to relate it to cutting desserts--pie or cake. With mix numerals and improper fractions, I talk about fitting the leftover cake or pie in the smallest number of containers. LOL Reducing fractions may be related to sharing a pie with the biggest pieces for the fewest number of people. Finding the LCDs so you can add or subtract fractions can be illustrated by cutting the pieces so each person gets the same size.

[MomtoJGJE]

I agree that manipulatives of some sort are awesome for fractions. Clocks are also great. In general, so far, my kids have understood fractions well before they are doing math on paper just because we talk about it when I"m cutting sandwiches or pie or pizza, etc.

[farmfamily]

Rightstart math has a linear model for fractions, which I think might help with this. You would first get a strip of paper (or cardstock) 12 inches long and about an inch wide. This would be the whole. Then get several more strips of paper exactly the same size. You can cut them in equal halves to show half (i.e. 6 inches), or in three inch strips to show quarters. Write 1/2 on the halves and 1/4 on the quarters. If you wanted to show twelfths you could cut them into 1 inch pieces, labeling each one 1/12. You can do this for all the fractions. Then you can lay them out. First the whole, then beneath it the 2 halves, then beneath that the three thirds, lining them all up below the whole. In this way it is easy to see the relationships between the fractions.

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I think i may not have explained the problem I am having well. DS understands fractions, but I can't figure out how to explain to him WHICH fractions need reducing. He gets the obvious ones, 4/8 is the same as 1/2, or 2/6 is the same as 1/3, but how do I explain that he should just KNOW that 8/12 is 3/4? I know by looking at it, and understanding the concept of LCD, which has not yet been taught in singapore. I teach him as best as possible from the textbook, but the workbook requires him to give answers in simplest form, without ever showing him how to tell which ones NEED reducing. Ugh.

We just muddled through as best as we could and trust it may be explained in the future, but i feel like each new concept is even MORE frustrating. Just a few pages later in the textbook on page 60 it wants me to show him how to find the value of 1/6 of 4, and 2/3 of 10. really? I need a calculator for that exact answer, and have NOOOO idea how to explain this to him.

Maybe this just isn't how i was taught, and maybe this is not a way that I can teach. I really like the concept of singapore, but I can't figure out how to use it. Is there a teacher's guide? I have an answer key, but it doesn't help me explain anything!!!

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lol, 8/12 is 2/3, not 3/4. Maybe i am the issue. I swear I did well in trigonometry and calculus! 4 children have depleted all of my brain cells.

[StephanieU]

If they haven't been taught the LCD, then I still think the best bet is to draw them/build them. Without understanding LCD, the only other option is guess and check. And really, that will take more time then building/drawing most of the time.