Sherning Tan's answer to Jackson R's Primary 6 Maths Fractions Singapore question.
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Pardon my drawing. Because this question requires "algebra" u can use the model method that i learned back when i was in pri school. Essentially it helps you understand where the "algebra" comes from. Most important part is understand that Fiction parts NOT EQUAL to Non Fiction parts (F is Fiction and NF is Non Fiction, so when you do the question you read it as 4 parts of Fiction Books and 4 parts of non fiction books). If need help understanding more just comment.
Date Posted:
4 years ago
What happened to 5/9 of friction, 3/7 of non friction?
The yellow words, instead of fractions i change it into model so we can work on full units. So 4/9 F we draw 9 squares n shade 5 the shaded 5 is loaned. Then for 4/7 we draw 7 units and shade 3, shaded is loaned. Remember that 5/9F means in 9 parts of F, 5 parts were loaned and 3/7NF means in 7 parts of NF, 3 parts were loaned.
So now we no longer have fractions in the equation but units instead.
But remember that 4 units of Fiction books is greater than 4 units of Non Fiction books so the every unit you draw for Fiction must be bigger than Non Fiction units. If you put 4/9F - 4/7NF = 48 and multiply everything into whole numbers you will not get (Left over Fiction) - (Left over Non Fiction) = 48.
So now we no longer have fractions in the equation but units instead.
But remember that 4 units of Fiction books is greater than 4 units of Non Fiction books so the every unit you draw for Fiction must be bigger than Non Fiction units. If you put 4/9F - 4/7NF = 48 and multiply everything into whole numbers you will not get (Left over Fiction) - (Left over Non Fiction) = 48.
According to your answer, friction 130, non friction 118.
130 x 4/9 - 118 x 4/7 not = 48, not tally with question
130 x 4/9 - 118 x 4/7 not = 48, not tally with question
Ye I tried to redo it when I got home & realised the F-NF=248 is wrong shld be 9F-7NF=248.
Since thats the case after redoing it, it seems like either (1)The total number was written wrongly or (2)The number of books left was written wrongly. ><
Since thats the case after redoing it, it seems like either (1)The total number was written wrongly or (2)The number of books left was written wrongly. ><
Thanks for your answers, I just realised that there is a typo in the question. It’s supposed to be 348 and not 248 books
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