Factors and primes
List the first five prime numbers.
2, 3, 5, 7, 11
Write the answer to this calculation in index form.
128 ÷ 125
123
Solve -42 ÷ 7
-6
Calculate 0.73 ÷ 0.01
73
Find 25% of 400.
400 x 25/100
= 4 x 25
= 100
Find the prime factorisation of 84.
84=22x3x7
Solve ∛729 + 52
∛729 + 52
=9 + 25
=34
16/2, -14, 2/7, 0
Which of the above numbers are integers?
16/2, -14, 0
Convert 8/33 into a decimal.
0.24 recurring
Decrease 385 by 20%.
385 x 20%
= 385 x 20/100
= 385 x 1/5
= 77
385 - 77 = 308
Find the prime factorisation of 456.
456=23x3x19
Solve
(34)5 ÷ 320
30 or 1
Solve 46 - 4 x (6 + 3)
46 - 4 x (6 + 3)
=46 - 4 x 9
=46 - 36
=10
Calculate 1/2 + 1 4/5 x 3 2/3
1/2 + 1 4/5 x 3 2/3
= 1/2 + 9/5 x 11/3
= 1/2 + 33/5
= 5/10 + 66/10
= 71/10
= 7 1/10
The population of a village went from 1800 to 1620. Find the percentage decrease in population.
1800 - 1620 = 180
180/1800 x 100% = 10%
Given the following numbers and their prime factors, find their HCF:
360=23x32x5
144=24x32
HCF=23x32
=72
Find the square roots of 81. Then, find the square roots of those numbers.
3, -3 and no solution
Round 5643 to 1s.f. and 2.0455 to 2s.f. (200 pts each)
6000 and 2.0
A person wishes to sell a 0.8ct (carat) diamond ring they bought at RM13000. You are given the following information:
A diamond loses at least 10% of its value the moment it is bought.
1ct = 0.2g
What is the weight of the diamond and what is its highest possible resale value? (200 points per correct answer)
0.8 x 0.2 = 0.16g
RM13000 x 0.9 = RM11700
A child's height went from 120cm to 150cm. What is the absolute increase? (200 points)
What is the percentage increase in height? (200 points)
Absolute increase = 150 - 120
= 30cm
Percentage increase = 30/120 x 100%
= 25%
A factory produces and sells a batch of 80 batteries at a time, while another factory produces and sells 60 phones at a time. How many batteries and phones does a company have to order to have the same amount of each?
80=24x5
60=22x3x5
LCM=24x3x5
=240
Write the answer to this calculation in index form.
81 x 33 ÷ 9
81 x 33 ÷ 9 = 34 x 33 ÷ 32
=37 ÷ 32
= 35
Given that the height of the Burj Khalifa is exactly 828m and that the height of Mount Everest is roughly 11 times the Burj, find the height of Mount Everest rounded to 1 s.f.
828 x 11 = 9108
=9000 (1s.f.)
Thomas and Julia went trick-or-treating and returned with bags of candies. Thomas' weighs 1 and 5/6kg, while Julia's weighs 2 and 2/9kg. Their parents tell them to split the candies evenly between the two of them. How much candy does each of them have now?
1 and 5/6 + 2 and 2/9
= 1 and 15/18 + 2 and 4/18
= 3 and 19/18
= 4 and 1/18
4 and 1/18 ÷ 2 = 2 and 1/36
In the year 2002, gold was priced at $300 per troy ounce. In 2005, the price went up by 60%. From 2005 to 2026, the price increased by another 1000%. Find the price of gold in 2026.
300 x (100%+60%) = $480
480 x (100%+1000%) = $5280