Q&A - P3 Math

[sembgal]

ammonite:

sembgal:

[quote=\"vinegar\"]Mary thinks of a 2-digit number.When the number is divided by 5, the remainder is 3.When the number is divided by 9, th remainder is 1. What is the number?

The answer is 40.
Working: 5 + 3 = 8
9 + 1 =10
The first common multiple of 8 and 10 is 40
8, 16, 24, 33, 40
10, 20, 30, 40

? 40 divided by 5 is 8, no remainder leh.

I don't know what the standard method is, but through deduction, my answer is 28.[/quote]Sorry, mistake on my part. Thanks for highlighting to me.
Working:
For Groups of 5 with remainder 3
5, 10, 15, 20, 25
If add 3= 8, 13, 18, 23, 28

For Groups of 9 with remainder 1
9, 18, 27
If add 1= 10, 19, 28

The answer is 28

[vinegar]

thanks sembgal…


will be great if there is someone able to modelize it

[vinegar]

another question:


Lynn has a box of 153 buttons.If she needs another 7 buttons so that every blouse she sews can have 5 buttons, how many blouses has she sewn?

[sembgal]

vinegar:

another question:


Lynn has a box of 153 buttons.If she needs another 7 buttons so that every blouse she sews can have 5 buttons, how many blouses has she sewn?

153 + 7 = 160
160 / 5 = 32
Answer: 32 blouses

[ammonite]

sembgal:

vinegar:

another question:


Lynn has a box of 153 buttons.If she needs another 7 buttons so that every blouse she sews can have 5 buttons, how many blouses has she sewn?

153 + 7 = 160
160 / 5 = 32
Answer: 32 blouses

I thought she wants to sew 32 blouses but has only sewn 30 since she still needs 7 buttons. How to interpret the question?

[sembgal]

ammonite:

sembgal:

[quote=\"vinegar\"]another question:


Lynn has a box of 153 buttons.If she needs another 7 buttons so that every blouse she sews can have 5 buttons, how many blouses has she sewn?

153 + 7 = 160
160 / 5 = 32
Answer: 32 blouses

I thought she wants to sew 32 blouses but has only sewn 30 since she still needs 7 buttons. How to interpret the question?[/quote]Hi Ammonite, yes. Thanks for pointing out to me.
153 + 7 = 160
160 / 5 = 32 blouses
7/5=1R2 ~ 2 blouses
32 - 2 = 30 blouses.
Yes, shortage of 7 buttons, therefore has to reduce by 2 blouses.
Therefore she has sewn 30 blouses

[ammonite]

sembgal:

Hi Ammonite, yes. Thanks for pointing out to me.
153 + 7 = 160
160 / 5 = 32 blouses
7/5=1R2 ~ 2 blouses
32 - 2 = 30 blouses.
Yes, shortage of 7 buttons, therefore has to reduce by 2 blouses.
Therefore she has sewn 30 blouses

Is it possible to just take 153 and divide by 5 to get the answer? She has sewn 30blouses with 3 remaining buttons.

The extra 7 buttons seem to be just a red herring to me.

[sembgal]

ammonite:

sembgal:

Hi Ammonite, yes. Thanks for pointing out to me.
153 + 7 = 160
160 / 5 = 32 blouses
7/5=1R2 ~ 2 blouses
32 - 2 = 30 blouses.
Yes, shortage of 7 buttons, therefore has to reduce by 2 blouses.
Therefore she has sewn 30 blouses

Is it possible to just take 153 and divide by 5 to get the answer? She has sewn 30blouses with 3 remaining buttons.

The extra 7 buttons seem to be just a red herring to me.

I suppose yes because the answer can be derived from quotient. Children need to use the method that they understand.

[kamom]

I am stuck Please help.


Danny and Mike shared some ice cream sticks equally. After Danny gave 20 ice cream sticks to Mike, Mike had twice as many ice cream sticks as Danny. How many ice cream sticks did each of them have at first? :thankyou:

[angel]

PapayaDad:

bbc:

Jeric had 45 marbles more than Mark. After Jeric lost 75 marbles, Mark had thrice as many marbles as what Jeric had left. How many marbles did Jeric have at first?

In the end :

M:UUU
J:U

at first (j not yet lost 75)

M:UUU
J:U +75 = 45 more than Mark = UUU + 45

U+75 = UUU + 45
2U = 30
U = 15

At first J have U+75 = 15 + 75 = 90
Mark have 3U = 3 x 15 = 45

Check J lost 75 = 15 ; Mark have 3 times more = 45. correct

Hi,

can you help explain using models?
This method looks like algebra.

Thank you very much.