Model Approach for Primary School Maths

Seniors & juniors algebra word problem

2011-02-27T19:09:00.005+08:00

The original question comes from http://homeschoolmath.blogspot.com/

Question

The total number of girls in the combined junior and senior classes is equal to the number of boys in those two classes. If the senior class has 400 students and the junior class has 300 students, and if the ratio of boys to girls in the senior class is 5:3, what is the ratio of boys to girls in junior class?

eBook - Model Approach For Primary School Mathematics

2011-02-26T21:39:00.005+08:00

Dear Readers,

I just published a eBook in LuLu.com. This ebook features 100 upper primary school problem sum questions with 'Model' answers. It costs only US$7.99.

Model Approach for Primary School Mathematics

Hope you find this useful. Thanks

Primary 5 Problem Sum

2011-02-26T11:16:00.002+08:00

Question

2/9 of the runners in a race are boys.3/7 of the remaining runners are men.1/4 of the rest are girls. There are 42 more women than girls. How many runners are there in the race?

Houses/workers/days problem

2010-11-05T23:54:00.003+08:00

Question

If 10 workers can build 3 houses in 60 days, how many workers are needed to build 5 houses in 40 days?

Primary 6 Question - ABCD is a square ....

2010-04-15T19:58:00.005+08:00

Question

ABCD is a square. RS=PR=QR and SQ is perpendicular to PR. Find angle SPQ ?

Primary 5 Question - 3 men, A,B, and C, worked together to paint a wall ...

2010-03-08T22:52:00.001+08:00

Question

3 men, A,B, and C, worked together to paint a wall. If the painting was done by one man, the time taken to complete the wall for A,B and C would have been 6hours, 8 hours and 12hours respectively. A and B had painted for 3hours after which A rested, B and C then continued with the painting. What would be the total number of hours taken to complete the wall.

Another Primary 5 Question

2010-02-04T21:35:00.001+08:00

Question

Adam and Rahmad shared some beads. If Adam gave 1/3 of his share to Rahmad, Rahmad would have 70 more beads than Adam. If Adam gave 1/5 of his share to Rahmad, Rahmad would have 10 more beads than Adam. How many beads does Adam have at first?

Primary 5 Question

2010-01-29T22:46:00.003+08:00

Question

2/7 of the number of girls was equal to 3/5 of the number of boys at a funfair. (a) what fraction of the number of children were girls? (b) There were 253 more girls than boys. How many girls were at the funfair.

Everyday Life Maths Question

2009-10-23T23:26:00.005+08:00

Here is the pricing for economy rice from a typical coffee shop.
The question is:

Question

Based on the pricing (first three from left to right), how much does the rice cost ? Also, based on all the four pricings, which one is considered not fair?

You see, maths question is everywhere. Just keep your eyes open.

PSLE 2009 Question

2009-10-14T20:26:00.002+08:00

Question

From ChannelNewsAsia: Jim bought some chocolates and gave half of it to Ken. Ken bought some sweets and gave half of it to Jim. Jim ate 12 sweets and Ken ate 18 chocolates. The ratio of Jim's sweets to chocolates became 1:7 and the ratio of Ken's sweets to chocolates became 1:4. How many sweets did Ken buy?

Primary 5 Question

2009-09-11T09:52:00.001+08:00

Question

20% of John's savings is $120 more than 30% of Brian's savings.
After John spends 5/6 of his savings, and Brian spends 1/2 of his savings, John has $20 more than Brian. How much did John and Brian save ?

Primary 6 Question

2009-08-29T18:16:00.000+08:00

Question

There were 40 more raisin buns than strawberry buns. After 3/4 of the raisin buns and 4/5 of the strawberry buns were sold, there were 28 buns left.

(a) How many strawberry buns were there at first?

(b) What fraction of the buns sold were raisin buns?

Distance/Speed/Time Question

2009-05-23T20:29:00.004+08:00

Question

This question came from my reader's comment

Distance between Town X and Y is 100km.
At 07:00, Sam left Town X and cycled towards Y.
Ann left Town X and cycled towards Y at 07:30.
Ann's cycling speed was 4 km/h faster than Sam. At 10:00, Ann caught up with Samuel. When Ann was 28 km from town Y, she stopped to wait for Samuel.

(a) How far was Samuel from Ann when she stopped to wait for him?

(b) How many minutes did Ann wait for Samuel?

Dear Readers

2009-03-17T10:47:00.002+08:00

Thank you for posting all the comments and questions. My primary goal of this blog is to show my readers that most (I would think 90%) of the primary school maths questions can be solved using model based approach. I hope you can learn some of the tricks along the way and able to guide your kid in their problem sum

FYI, I will try to answer your questions if you also give it a try.

Hope this blog can help the parents as well as the kids.

Primary 6 Problem Sum

2009-03-16T21:03:00.002+08:00

Question

A box contained 50¢ coins and 20¢ coins in the ratio 2:3. When I took out four 50¢, exchanged them for 20¢ coins, and put then put the money back into the box, the ratio became 2:7. Find the sum of money in the box.

Answer

Six Steps to Model Approach

2008-11-19T22:15:00.004+08:00

I will be using this question to illustrate my six step approach in solving problem sum.

Questions

Aminah and Belinda each has some money. If Aminah spends $8, the ratio od the amount of money Aminah has to the amount of money Belinda has becomes 2:3. If Belinda spends $8, the ratio of the amount of money Aminah has to the amount of money Belinda has will be 11:14. How much money do they have altogether?

Answer

Primary 4 Problem Sum

2008-11-14T22:07:00.002+08:00

Question

A fruit seller brought 350 apples for $140. 30 apples were rotten. He packed the rest in packets of 4 and sold each packet for $1. How much money did he lose from sale ?

Answer

Primary 4 Problem Sum Question

2008-11-01T11:58:00.002+08:00

Question

Gilian spent 1/3 of her salary each month, gave 2/5 of it to her mother and saved the rest. If she saved $400 each month, what is her total salary ?

Answer

Primary 4 Problem Sum ... Suzanne baked tarlets...

2008-10-23T20:27:00.003+08:00

Question

Suzanne baked 1200 tartlets. She gave 1/2 of them to her mother and 1/4 of the rest to her sister. How many tartlets did she have left ?

Answer

Primary 4 Problem Sum, ... Two Pails, A and B, ...

2008-10-21T22:03:00.003+08:00

Question

Two pails, A and B, contain 1 litre 900 ml of water altogether. After 680 ml of water is poured from pail A into pail B, the amount of water in each pail is the same. How much water was in pail A at first ? Give your answer in litre and ml.

Answer

Introduction

2008-10-10T22:04:00.000+08:00

Singapore primary school mathematics has adopted the "Model Approach" in solving "Problem Sum" questions some years ago. I started to learn and practice this method when my daughter was in Primary Five 4-5 years ago and I found it extremely useful. The technique looks very different from the traditional method I learned during my school time. However, once you master the basic I believe all (almost) problem sum questions can be tackled with ease, hopefully :-).

In this blog, I hope to convince you that we do not have to use algebra (eg, x=3y+4, y=x-2) to solve your kid's primary school mathematics. As the proverb says "A Picture Is Worth A Thousand Words", I will use models instead of spending a lot of words in trying to explain how I come to the solution.

A few tips in starting your "model":

Start drawing blocks on the paper, you don't have to draw in scale. Just draw it neatly.
Label things, people, ...
Put in the known number(s)
Put in question mark(s) to indicate unknown to be found.
Assign a "u" unit for easy reference, if applicable
Do not put too many details in one model, try to use a few models and draw vertical lines to ensure alignment.

Below shows two sample models for most of the typical questions.