many mistakes in Singapore 3B

[Gwenny]

They go over how to change, but they always have you change only one of the denominators to what the other one is. I don't see an explanation of having to find a higher multiple of both numbers. Unless I'm totally missing it-which is entirely possible. on pg 74TB, number 10, a and b are comparing but it's easy to just change the lower denominator fraction to the higher to compare, like the bubbles show you right above. Then c, you have to change both denominators to something completely different to compare. Am I missing something? (btw, I know how to do it, just missing how they show them--maybe they want to see what they can figure out?)

[Nealewill]

I think I see what you mean. For F of part 3 on page 75 it asks which is higher, 3/5 or 5/8. I don't think they are expecting the kids to come up with common denominators. I think if you drew the pie and colored in 3/5 on the pie and then 5/8 on the pie you would "see" one of them is bigger. Now, they are practically the same so this would definitely be tricky! For your dd, I would probably just help her color in the pie pieces. She might be able to see that 3/5 is more than 5/8 and she might not. Even 10/12 versus 4/5 (part C) is pretty tricky. 10/12 is barely more than 4/5. If it were me, I would just help her draw the pies and then have her compare what is more. Make sense? I wouldn't spend a lot of time on it and I would just help her to see how they are different. But level 4 and 5 are going to touch on this a lot more deeply. This is just an intro IMHO of comparing these amounts to see that they are different. To me, it is more important that she understand how to create the pie and understand what 10/12 means than to compare them. I am always surprised at how many kids don't actually "understand" fractions and what they mean and that makes higher level math much more difficult for them.