James Chi
Asked 9 years ago

SG chevron_right Primary 3 chevron_right Number and Algebra

Replies 12

Chris Rogers

Two Digit > 9 Remainder 6 8, 16, 24 14, 22, 30 9, 18, 27, 12, 21, 30, Answer is 30 Three Digit > 99 96, 104, 112, 120 102, 110, 118, 126 99, 108, 117 102, 111, 120 Answer is 102

6 years ago
Zhong Shu Hao

Remember: 1000 is a product of 8 while 999 is a product of 9. So From here, list down the possible numbers. 998 996 990 987 982 976 974 968 966 979 978 970 970 …… Hence, the number is 970.

6 years ago
Zhong Shu Hao

The left column are the numbers that give a remainder of 6 when divided by 8, while the right column are the numbers that give a remainder of 3 when divided by 9.

6 years ago
Yeo See Yeong

is it possible to have a formula, in case the listing of these combination is long?

6 years ago
Meng Khim Goh

Zhong Shu Hao the right column doesn't give remainder of 3 when divided by 9

6 years ago
Zhong Shu Hao

oh... oops i will correct it

6 years ago
Zhong Shu Hao

Remember: 1000 is a product of 8 while 999 is a product of 9. So From here, list down the possible numbers. 998 993 990 984 982 975 974 966 966 …… Hence, the number is 966.

6 years ago
Zhong Shu Hao

er... by observation I guess... As you can see, the left column starts from the number 998 while the left column starts from 993, which is 5 less. But as the right column decreases at a greater rate, we will try to make the number in the left column SMALLER than the number in the right column, and the numbrr will be 990, which is 3 less than the number in the right column. Since the right column -9 each time and the left column -8 each time, the right column -1 extra than the left column each time. To end up with the same numbers in both columns, the right column must minus 3x9 while the left column must minus 3x8. 993 - 3x9 =993-27 = 966 990 - 3x8 =990-24 = 966

6 years ago
Chris Rogers

My bad, greatest number for part b) not smallest. As for a formula, not really. Besides this is a P4 question (of course can be given to P5 and P6) however this is introduced at P4 as part of factors and multiples and thus a formula would not be provided. Typically, the questions will be designed such that the listing does not need to be too long.

6 years ago
Zhong Shu Hao

Primary sch Q tests quite a bit on observation skills... whether in this kind of questioms or models, or patterns (needless to say :D )

6 years ago
James Chi

Thanks for your input :-)

6 years ago
James Chi

Btw guys, this question came out from a p3 assessment book.

6 years ago

Sirlina Lee
Asked 9 years ago

SG chevron_right Primary 5 chevron_right Number and Algebra

Please help for this P5 question. Thank you!😄

Replies 1

Chris Rogers

A similar question was posted not long ago.... https://www.facebook.com/photo.php?fbid=1447643575547894&set=gm.461776310645697&type=1

6 years ago

Meenu Ashwin
Asked 9 years ago

SG chevron_right Primary 5 chevron_right Number and Algebra

Pls help me with this question!

Replies 3

Chris Rogers

Hi there. This is pretty much the same as this question https://www.facebook.com/photo.php?fbid=10153333265138708&set=p.10153333265138708&type=1&theater

6 years ago
Chris Rogers

This original question is here https://www.facebook.com/photo.php?fbid=10205091566463649&set=gm.461028260720502&type=1&theater

6 years ago
Meenu Ashwin

Thx

6 years ago

Daphne Hwee Lan Chua
Asked 9 years ago

SG chevron_right Primary 4 chevron_right Number and Algebra

Can someone please advise what's the best method to solve this P4 question? TIA

Replies 5

Zhong Shu Hao

What we can realise is that if we add 40, 56 and 60 together, the value we get is 2 times of the sum of what the 3 boys have altogether.

6 years ago
Yeo See Yeong

6 years ago
Vincent Ong

Jimmy + Muthu (56) plus Peifen + Muthu (60) = Peifen + Jimmy + Muthu + Muthu = 116. Since Peifen + jimmy = 40, Muthu + Muthu = 116-40, Muthu = 76/2 = 38.

6 years ago
Yueh Mei Liu

6 years ago
Daphne Hwee Lan Chua

Thank you so much for the solutions. Now it makes sense.

6 years ago

Lan Nguyen
Asked 9 years ago

SG chevron_right Primary 3 chevron_right Number and Algebra

P3 question. Thanks all

Replies 2

Zhong Shu Hao

Suppose all are man. The amount of donated will be 13x$8=$104. But the actual amount of money donated is $139, which is $35 more. This $35 is due to the $7 extra that each woman donates. Hence, there will be $35/$7 = 5 women. Thus, there are 13-5=8 men.

6 years ago
Amy Aw

6 years ago