Finding 100%

Maths

Growth and decay

If 75% of a number is 150, what is my number?

If I buy a car in a 20% off sale and it costs £30,000, how much did the car originally cost?

If I decreased the amount I paid for my car insurance by 90% to £36.50 per year, how much did I pay previously for my car insurance?

If a jumper was marked as 56% off and costs £50 now, then 44% of the original cost of the jumper is equal to £50

If I know something costs £2.10 in a 30% off sale, then I would calculate £2.10 = 70% and scale accordingly to get that 100% = £3 to find the original amount.

If the amount of flour in a bag increased by 20%, it would always mean we add 20g on to the amount.

If I increase 200kg by 30%, then the new amount I have is...

The decimal multiplier to increase an amount by 53% would be...

It is possible to increase an amount by more than 100%

If you decreased an amount by 60%, the decimal multiplier would be 1.60.

This lesson will be removed by end of Summer Term 2025.

Finding 100%

Lesson outcome

This lesson will be removed by end of Summer Term 2025.