P5- BODMAS

Note: '/' means 'divided by'

(a) (2x3+4)-(3x2)x6=
(b) (15x24)+(9/3)x$5=
(c) (15x9+9)/3x$5=
(d) 15x24+(9/3x$5)=
(e) (15x24)+9/(3x$5)=
(f) 59-(5+27)/4+12=
(g) (570-50)/(16+24)=
(h) 750/5x3=
(i) (18+2)x(30+60)=
(j) 72/4+2=
(k) 80+5x6=
(l) 29-36/3=
(m) 270/5x6+1=
(n) (560+280)/(40-26)=
(o) 5+740/10/2=

P6 Problem Sums Dec '08

1. Ben bought 3 times as many toy cars as game cartridges. He spent $1615 altogether. A game cartridge costs $15 more than the total cost of game cartridges. Find the cost of a game cartridge.

2. Mrs Lin bought 12 pears and 4 apples. Mrs Wang bought 12 apples and 4 pears. Mrs Wang paid $1.60 less than Mrs Lin. If an apple costs 35 cents, how much did a pear cost?

3. Limei went to the market with $48. This amount of money was just enough to buy 4kg of beef and 3 kg of mutton. Limei, however, bought 3kg of beef and 4 kg of mutton and had $1.50 left. Find the cost of 1kg of mutton.

4. Mr Fu paid $404 for some jackets and T-shirts. A jacket cost $20 and a T-shirt was $8 cheaper than the jacket. If he bought 7 more T-shirts than jackets, how many jackets and how many T-shirts did he buy?

5. On tree-planting day, 40 pupils planted some trees. Each boy planted 3 trees and each girl planted 2 trees. The boys planted 30 more trees than the girls. How many boys were there?

6. Box A contains 50-cent coins and Box B contains 20-cent coins. There are 19 more coins in Box B than in Box A. But the amount of money in Box A is $1.30 more than the amount of money in Box B. How much money was there in Box A?

7. A big tank had 890 litres of water. A small tank had 170 litres of water. When an equal amount of money was added to both tanks, the big tank had 3 times as much water as the small tank. How much water was added to each tank?

8. Ann, Ben and Mike spent $566. Ann spent $176 more than Ben and Mike spent $60 less than Ben. How much Ben spend?

9. Jane is thinking of a number. When it is divided by 6, the quotient is a whole number. When it is divided by 9, the quotient is also a whole number. What is the number?

10. Susan wants to arrange her stamps in columns on a card. If she puts 8 stamps in each column, she will have 2 stamps left. If she puts 9 stamps in each column, she will be short of 4 stamps. How many stamps does she have?

P6 Problem Sums Dec '08

P5- Solar System

Rotation of the Earth

• The Earth rotates on its own axis from West to East. 
• The axis is an imaginary line that passes through the North Pole and the South Pole.
• It takes about 24 hours (one day) for Earth to complete one rotation.
• At any one time, one side of the Earth will be facing the Sun.
• The half side of Earth facing the Sun will experience day.
• The other half side of Earth facing away from the Sun will experience night.
• It takes 24 hours for a place on Earth to come back to the same position.
• The rotation of Earth brings about day and night.

The Atmosphere

• The atmosphere is a layer of air surrounding the Earth.
• The atmosphere is important to us in various ways
  

1. It acts as a blanket that retains some heat from the Sun, thus keeping the temperature on Earth fairly steady.
2. It protects Earth from the harmful ultra-violet rays from the Sun.
3. The oxygen in the atmosphere is used for respiration.
4. The carbon dioxide in the atmosphere is used for photosynthesis.
5. The other gases in the atmosphere are required for many other processes.

Importance of the Sun

• The light energy given out by the Sun enables plants to photosynthesize, thus enabling the survival of all living things because all living things depend directly or indirectly on plants for food.
• The light energy given out by the Sun enables animals to see and respond to changes in their surrounding.
• The heat energy given out by the Sun keeps organisms warm and provides a suitable temperature for various life processes to take place.
• The heat energy given out by the Sun enables the evaporation of water, thus ensuring the continuity of the water cycle to provide a continuous source of water supply to the organisms on Earth.

Position of the Earth from the Sun

• If the Earth were nearer to the Sun, the Earth would receive too much heat energy and the temperature would increase drastically. The oceans would dry up and most living things would die because of the heat.
• If the Earth were further from the Sun, the Earth would receive too little heat from the Sun and the temperature would fall. The oceans would freeze and most living things would not be able to survive the cold weather. 

REMINDER: Please read up on this chapter in your science guide book.

P6 - Algebra

To be handed in on 11 nov 2008

Simplify the following:
1. (a) 5a+3a-6a
(b)3a+4b-a-b
(c)5x+7y+3z-2x-4y+z
(d)12xy-13xz+5yz-4xz
(e)3a-4a+5a-7a+4
(f)5ab-1.5ab+0.75bc+0.25cb

2. (a)3a-5a+4a
(b)12a+5b-7a-14b-9a
(c)2p-5q+7r-4p+2q-3r
(d)7abc-4bca+6cba-cba
(e)a+b+c+2b-c+3c+a
(f) 2ab+3bc+5ac-5ba+2cb+5ab