KNEC SAMPLE GRADE 9 REVISION
Lowest Common Multiple - *correct answer*The Lowest number in the two numbers
time tables. ie, 18 and 24, so they both have 72 which is the lowest common multiple.
Prime Factors - *correct answer*Prime numbers that multiply to achieve a chosen
number. ie, 110 > 2 x 55, 55 isn't prime so do the same, 55 > 11 x 5, both prime, so
prime factors of 110 are, 2 x 5 x 11. (you always have to divide the number by a chosen
prime, 2 is a good choice)
Highest Common Factor - *correct answer*The highest factor of two numbers. ie, 28
and 16, they both have 2 and 4, 4 is higher so that is the highest common factor.
BIDMAS - *correct answer*Brackets, Indices, Division, Multiplication, Addition,
Subtraction.
Adding and Subtracting Fractions - *correct answer*The denomination has to be the
same. If it is different find the lowest common multiple of the denominators. 5/6 - 3/4
=5/6 x 2/2 - 3/4 x 3/3 = 10/12 - 9/12 = 1/12.
Reciprocal - *correct answer*The number divided into 1. reciprocal of 2 is 1/2 reciprocal
of a fraction is the fraction turned upside down 3/6 > 6/3.
Negative reciprocal - *correct answer*The same as reciprocal but putting a negative in
front when there isn't one and taking one away when there is one.
Increasing by a percentage - *correct answer*Multiply the number by 1 + (the
percentage increase / 100) ie, increase 6£ by 5%, 6 x 1.05 = £6.30
Decrease by a percentage - *correct answer*Multiply the the number by 1 - (the
percentage decrease / 100) ie, decrease £8 by 7%, 8 x 0.93 = £7.44
Mode - *correct answer*The number that comes up the most (most likely value, non
numerical ie weather patterns.)
Median - *correct answer*The number directly in the middle (Data with extreme value)
Mean - *correct answer*The average (Balanced spread of values)
The range - *correct answer*The difference between the largest value and smallest
value
Stem and leaf diagram - *correct answer*
