Primary School Math

[Scrooball (clone)]

Examples

1) Tom and Jerry shared a box of marbles. If Tom was given 10 fewer marbles, Jerry would have five times as many marbles as Tom. If Tom was given 10 more marbles, he would have ½ as many marbles as Jerry. What percentage of the marbles did Tom receive?

2) Candle A and candle B are of the same length. Candle A, which is broader, can burn for 5 h while Candle B, the thinner candle, can burn for 4 h. If both candles are lighted at the same time, how long does it take for Candle A to be twice as long as Candle B?

3) Mrs Reuten bought some pizzas for a group of children. The girls received thrice as many pizzas as the boys. There were an equal number of girls and boys. Each boy ate 2/9 of a pizza and the boys finished all the pizzas given to them. Each girl ate 1/6 of a pizza and the girls had 4½ pizzas left. How many pizzas did Mrs Reuten buy?

4) A group of 328 P5 children were divided into two teams at the P5 camp this year. There were 8 more children in Team B than in Team A. There were also 50% more boys in Team B than in Team A. If 3/8 of the girls were in Team B, (a) what percentage of the pupils in Team B are girls? (b) what percentage of the children are boys?

 

[erection2015]

for sure i cant do. Its just too difficult these days.

 

[YellowRibbon]

Examples

1) Tom and Jerry shared a box of marbles. If Tom was given 10 fewer marbles, Jerry would have five times as many marbles as Tom. If Tom was given 10 more marbles, he would have ½ as many marbles as Jerry. What percentage of the marbles did Tom receive?

2) Candle A and candle B are of the same length. Candle A, which is broader, can burn for 5 h while Candle B, the thinner candle, can burn for 4 h. If both candles are lighted at the same time, how long does it take for Candle A to be twice as long as Candle B?

3) Mrs Reuten bought some pizzas for a group of children. The girls received thrice as many pizzas as the boys. There were an equal number of girls and boys. Each boy ate 2/9 of a pizza and the boys finished all the pizzas given to them. Each girl ate 1/6 of a pizza and the girls had 4½ pizzas left. How many pizzas did Mrs Reuten buy?

4) A group of 328 P5 children were divided into two teams at the P5 camp this year. There were 8 more children in Team B than in Team A. There were also 50% more boys in Team B than in Team A. If 3/8 of the girls were in Team B, (a) what percentage of the pupils in Team B are girls? (b) what percentage of the children are boys?

This is Primary school maths ???!!!

How the hell am i going to teach my future children .... ?

 

[Raiders]

Math was my lousiest subject in school. Seeing all these questions makes my head ache.

 

[erection2015]

but you got A* and A1 for tackling girls right?

Math was my lousiest subject in school. Seeing all these questions makes my head ache.

 

[Boliao]

1) Tom and Jerry shared a box of marbles. If Tom was given 10 fewer marbles, Jerry would have five times as many marbles as Tom. If Tom was given 10 more marbles, he would have ½ as many marbles as Jerry. What percentage of the marbles did Tom receive?

Assuming Tom has X marbles, then

(X-10) + 5 (X-10) = (X+10) + 2 (X+10) {number of marbles do not change}
6X - 60 = 3X + 30
3X = 90
X = 30 {Tom has 30 marbles}

Verifying the equation; If Tom has 20 marbles, Jerry would have 100 marbles (checked). If Tom has 40 marbles, Jerry would have 80 marbles.

Total number of marbles is therefore, 120.

Tom's share is 30/120 or 25%

 

[The_Hypocrite]

Ask LHL...he has some high end qualification in maths right? paid for by singaporeans tooo

 

[vamjok]

Assuming Tom has X marbles, then

(X-10) + 5 (X-10) = (X+10) + 2 (X+10) {number of marbles do not change}
6X - 60 = 3X + 30
3X = 90
X = 30 {Tom has 30 marbles}

Verifying the equation; If Tom has 20 marbles, Jerry would have 100 marbles (checked). If Tom has 40 marbles, Jerry would have 80 marbles.

Total number of marbles is therefore, 120.

Tom's share is 30/120 or 25%

talk cock, use algebra i also can solved. you are not supposed to use it at pri sch level. this is where all of us here find it tough

 

[chonburifc]

talk cock, use algebra i also can solved. you are not supposed to use it at pri sch level. this is where all of us here find it tough

Yes, cannot use Algebra to solve. Have to use 'units' and 'blocks' or something similar at Primary level. Familiar with these as I was helping my nieces/nephews a few years back and I thought my mathematics is powderful.

 

[vamjok]

Yes, cannot use Algebra to solve. Have to use 'units' and 'blocks' or something similar at Primary level. Familiar with these as I was helping my nieces/nephews a few years back and I thought my mathematics is powderful.

what i did was when i was teaching a p5 kids few years back was i solved using algebra first. Then i teach her how to solve but merely replacing the unknown variable x with - blocks, if got more than 1 variable like y replace with triangle. LOL

in the end i really gave up. LOL its really very hard to teach maths to kids

 

[Alamaking]

I scored an A in math, but I agree this is too difficult for a primary school student, sec 1 or 2 also might have problem....

 

[halsey02]

I will loose my 'marbles' if I try to solve the questions, but my 'candle' is definitely "A", I will check with "ah Mei" this weekend and check how long a time I can go, before she gets "BURN".

 

[Jah_rastafar_I]

wah our primary school kids will be geniuses when they go to JC or poly. I bet in future primary school kids will be doing university level math.

 

[erection2015]

thats better than BosSam....he scored D.

I scored an A in math, but I agree this is too difficult for a primary school student, sec 1 or 2 also might have problem....

 

[Boliao]

talk cock, use algebra i also can solved. you are not supposed to use it at pri sch level. this is where all of us here find it tough

Honestly, I did not know you cannot use algebra; the question did not state that either. I just did a Google and Primary 5 syllabus does includes algebra. How would you solve it by units/blocks?

 

[loneshark]

Examples

1) Tom and Jerry shared a box of marbles. If Tom was given 10 fewer marbles, Jerry would have five times as many marbles as Tom. If Tom was given 10 more marbles, he would have ½ as many marbles as Jerry. What percentage of the marbles did Tom receive?

Situation 1: T has 10 fewer, ratio T:J is 1:5. Total units is 6
Situation 2: T has 10 more, ratio T:J is 1:2. Total units is 3. Multiply by 2 to make Situation 1 and Situation 2 to be same total units. Now T:J is 2:4.
Now compare, situation 1 and 2. T has difference of 2-1 = 1 unit, representing a physical difference of 20 marbles.
Therefore 1 unit is 20 marbles. Total 6 units is 20X6 = 120 marbles.
T's orginal share is 20+10 = 30 marbles, or 30/120 = 25%.

Tio bo?

 

[zhihau]

Honestly, I did not know you cannot use algebra; the question did not state that either. I just did a Google and Primary 5 syllabus does includes algebra. How would you solve it by units/blocks?

bro,
best source is the syllabus from MOE, P5 & P6 only taught basic algebra. the questions in TS's post can leave the P6s leaving the PSLE exam hall crying :o:o:o

 

[zhihau]

Tio bo?

bro,
ever considered joining the teaching fraternity? they need people like you

 

[loneshark]

Tutoring is big money business!
Jokes aside, helping kids with their Maths is quite a workout these days, helps prevent Alzheimer's!
But back to the original point, I really don't see any real life application of these puzzles.

 

[Boliao]

Situation 1: T has 10 fewer, ratio T:J is 1:5. Total units is 6
Situation 2: T has 10 more, ratio T:J is 1:2. Total units is 3. Multiply by 2 to make Situation 1 and Situation 2 to be same total units. Now T:J is 2:4.
Now compare, situation 1 and 2. T has difference of 2-1 = 1 unit, representing a physical difference of 20 marbles.
Therefore 1 unit is 20 marbles. Total 6 units is 20X6 = 120 marbles.
T's orginal share is 20+10 = 30 marbles, or 30/120 = 25%.

Tio bo?

WTF.. I can only understand up to that part where you arrive at 1 unit = 20 marbles based on the ratio. And the government wonders why we do not want to have kids.