GCSE Secondary Maths Age 13-17 - Number: Number machines - Explained

The video tutorial explains a number machine that multiplies an input by 3 and subtracts 4 to produce an output. It covers three parts: calculating the output for a given input, reversing the process to find the input for a given output, and finding an input where the input and output are equal. The tutorial uses examples and algebraic methods to solve these problems, emphasizing understanding of input-output machines and reversing operations.

What is the output when the input to the number machine is 4?

• 12

• 6

• 8

• 10

If the output of the number machine is 11, what was the input?

• 6

• 3

• 4

• 5

Which operation is NOT part of reversing the number machine process?

• Adding 4

• Dividing by 3

• Multiplying by 3

• Subtracting 4

What equation is used to find the input where input equals output?

• x - 4 = 3x

• x + 4 = 3x

• 3x - 4 = x

• 3x + 4 = x

What is the input value where the input and output are the same?

• 1

• 4

• 2

• 3