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primary 5 | Maths
| Whole Numbers
4 Answers Below
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Please help. Thank you in advance.
Date Posted: 5 years ago
Views: 641
120 - 18 = 102
102 marbles → (red + green) = blue
102 marbles = 2 x blue
So blue marbles = 102 ÷ 2 = 51
120 - 16 = 104
104 marbles → (red + blue) = green
104 marbles = 2 x green
So green marbles = 104 ÷ 2 = 52
It is easy to find the number of red marbles now.
102 marbles → (red + green) = blue
102 marbles = 2 x blue
So blue marbles = 102 ÷ 2 = 51
120 - 16 = 104
104 marbles → (red + blue) = green
104 marbles = 2 x green
So green marbles = 104 ÷ 2 = 52
It is easy to find the number of red marbles now.
May l trouble you to explain this question to me again?
Red + green marbles is 18 more than blue marbles. So the idea is to make them the same number first by taking away that 18 marbles.
Now, you have the same number of blue as green+red. So that's as good as saying the total marbles now is twice the number of blue marbles. Then you can find how many blue marbles there are.
The method to find the number of green marbles is the same.
Now, you have the same number of blue as green+red. So that's as good as saying the total marbles now is twice the number of blue marbles. Then you can find how many blue marbles there are.
The method to find the number of green marbles is the same.
I'm still slightly confused. I'll try drawing a model and see whether I can solve it. Thank you very much for your kind help
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Red and green more than blue means R + G - B.
Date Posted:
5 years ago
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Is my model correct?
Date Posted:
5 years ago
You might want to draw dotted lines for your 2u instead of bold lines. If not it would make it look like the number of red and blue /red and green marbles ares the same
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Hi purpleolive, this is how you get the 2 blue unit.
Date Posted:
5 years ago
Thank you so much Henry! I'll go through with my child again.
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Is this better?
Date Posted:
5 years ago
Grateful thanks for rendering your help. It looks like my child is still confused why there are two times of blue marbles.
In that case can i suggest this... Use smaller numbers for this question, say R +G =9, B = 3. Total =12. Take 12 counters, say beads or lego bricks, only need to differentiate for blue color; for red n green, the colors don't matter as we are solving for blue. After that, 'act it out'. All the best for your child.
Okay, we will try again. Thank you so much for your time. Have a lovely evening ahead!
It's not that there are 2x of blue marbles. It's that when we make the number of (green+red) marbles equal to the number of blue marbles, the total number of marbles is the same as 2 times the number of blue marbles.
It's like saying ,
green+red marbles = 1u.
Blue marbles = 1u
Total = 2u = 102
So we can use this knowledge to find how many blue marbles there are.
It's like saying ,
green+red marbles = 1u.
Blue marbles = 1u
Total = 2u = 102
So we can use this knowledge to find how many blue marbles there are.
Yup, from MODEL, if you 'cut away' the 18 from (R+G), the NUMBER of (R+G) = NUMBER of blue marbles. It is TANTAMOUNT to 2 groups of blue marbles. Cheers.
Yup tutor Phylicia is right. Hope your child can understand
Dear tutors, thank you very much for helping us.
Thank you for the steps and the answer to the question . Thank you and I will practice on it further. Have a great day ahead.
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