Grade 9 revision

Indices

100

Simplify the following expression:
3a⁴ * 2a 

6a⁵

200

Write the following number on scientific form:
810 000

8.1 x 10⁵

300

Simplify the following expression:
2m⁴n³ * 4m⁷n⁶ * 2mn^-2

16m¹²n⁷

400

Simplify the following expression:
(x²y²)³/xy⁶

x⁵y

500

Convert the following to numeral form:
9.925 x 10^-4

0.0009925

Algebra

100

Expand and simplify:
4(7x+8) + 8(5x-7) 

68x - 24

200

Expand and simplify:
(2x+5)(2-4x)

10 - 8x² - 16x

300

Factorize the following:

2x²+14x+20

(x+2)(2x+10)

400

Solve the following:
5x - 2 > 4 + 3x

x > 3

500

Solve for x and y:
(1) 5x + 3y = 41
(2) 2x + 3y = 20

x = 7 and y = 2

Statistics

100

Find the mean of the following set of data: 13, 23, 21, 20, 21, 24, 18

Mean = 20

200

What is the median of the following data: 9, 5, 3, 8, 9, -2, 10, 9, 5, 13

Median = 8.5

300

What is the mode of the following data: 2, 2, 5, 4, 2, 3, 6, 1, 0, 3, 3, 3, 2, 5

Mode = 2 and 3

400

True or false:
In a box-and-whisker plot, the box portion represents the data between the first and third quartile values.

True

500

Find the standard deviation of 5, 7, 4, 9, 10.

St. dev = 2.3

Trigonometry

100

When using Trigonometry, the side "touching" the known angle is called the what?

Adjacent

200

When using Pythagoras Theorem, what is the formula to calculate side b?

b=√(c²−a²)

300

sin(θ)=

opposite / hypotenuse

400

When using Trigonometry, what formula is used to calculate the adjacent side when given the Hypotenuse and an angle?

a=h * cos(θ)

500

Ayesha walks 13m north, turns 90 degrees east and then walks 3m forward.
How far is Ayesha from where she started?

13.34m

Random

100

What's the biggest animal in the world?

The blue whale

200

What year was Heinz established?

1869

300

What was the most streamed show on Netflix in 2020?

The Umbrella Academy season 2

400

What is the name of Nemo's dad in Finding Nemo?

Marlin

500

What is the biggest island in the world?

Greenland