mr barton maths

0:00

Percentages of an Amount (Non-Calculator)

Select the skills to practice, and then click Go!

Foundational Skills
Find 50% of an amount
\[ 50\% \text{ of } 84 = 42 \]
Find half of a number by dividing by 2.
Find 25% of an amount
\[ 25\% \text{ of } 120 = 30 \]
Find a quarter of a number by dividing by 4.
Find 10% of an amount
\[ 10\% \text{ of } 350 = 35 \]
Find 10% of a number by dividing by 10.
Find 1% of an amount
\[ 1\% \text{ of } 400 = 4 \]
Find 1% of a number by dividing by 100.
Find 5% of an amount
\[ 5\% \text{ of } 80 = 4 \]
Find 5% by finding 10% and halving.
Multiples of 10%
Find 20% of an amount
\[ 20\% \text{ of } 150 = 30 \]
Find 20% by finding 10% and doubling.
Find 30% of an amount
\[ 30\% \text{ of } 120 = 36 \]
Find 30% by finding 10% and multiplying by 3.
Find 40% of an amount
\[ 40\% \text{ of } 150 = 60 \]
Find 40% by finding 10% and multiplying by 4.
Find 60% of an amount
\[ 60\% \text{ of } 80 = 48 \]
Find 60% by finding 10% and multiplying by 6.
Find 70% of an amount
\[ 70\% \text{ of } 90 = 63 \]
Find 70% by finding 10% and multiplying by 7.
Find 80% of an amount
\[ 80\% \text{ of } 150 = 120 \]
Find 80% by finding 10% and multiplying by 8.
Find 90% of an amount
\[ 90\% \text{ of } 120 = 108 \]
Find 90% by finding 10% and multiplying by 9.
Combined Percentages
Find 15% of an amount
\[ 15\% \text{ of } 80 = 12 \]
Find 15% by adding 10% and 5%.
Find 35% of an amount
\[ 35\% \text{ of } 120 = 42 \]
Find 35% by combining 10% chunks and 5%.
Find 45% of an amount
\[ 45\% \text{ of } 80 = 36 \]
Find 45% by combining 10% chunks and 5%.
Find any percentage using 1%
\[ 3\% \text{ of } 200 = 6 \]
Find any percentage by finding 1% first.
Greater than 100%
Find 200% or 300% of an amount
\[ 200\% \text{ of } 45 = 90 \]
Find multiples of 100% by multiplying.
Find 150% of an amount
\[ 150\% \text{ of } 60 = 90 \]
Find 150% by finding 100% plus 50%.
Find 125% of an amount
\[ 125\% \text{ of } 80 = 100 \]
Find 125% by finding 100% plus 25%.
Find 110% or 120% of an amount
\[ 110\% \text{ of } 70 = 77 \]
Find 110% or 120% by adding to 100%.
Expressing as a Percentage
Express as a percentage (total of 100)
\[ 24 \text{ out of } 100 = 24\% \]
Write a quantity out of 100 as a percentage.
Express as a percentage (total of 10 or 50)
\[ 7 \text{ out of } 10 = 70\% \]
Write a quantity out of 10 or 50 as a percentage.
Express as a percentage (total of 20 or 25)
\[ 12 \text{ out of } 20 = 60\% \]
Write a quantity out of 20 or 25 as a percentage.
Express as a percentage (total is a multiple of 100)
\[ 240 \text{ out of } 400 = 60\% \]
Write a quantity as a % when total is a multiple of 100.
Reverse Percentages
Find the original given 50%
\[ 50\% = 36 \rightarrow ? = 72 \]
Work backwards from 50% to find the original.
Find the original given 25%
\[ 25\% = 18 \rightarrow ? = 72 \]
Work backwards from 25% to find the original.
Find the original given 10%
\[ 10\% = 15 \rightarrow ? = 150 \]
Work backwards from 10% to find the original.
Find the original given 20% or 30%
\[ 20\% = 24 \rightarrow ? = 120 \]
Work backwards from 20% or 30% to find the original.
Find the original given 5%
\[ 5\% = 8 \rightarrow ? = 160 \]
Work backwards from 5% to find the original.
Find the original given 1%
\[ 1\% = 7 \rightarrow ? = 700 \]
Work backwards from 1% to find the original.
Special Cases
Find 75% of an amount
\[ 75\% \text{ of } 120 = 90 \]
Find 75% by finding 50% plus 25%.
Find 33⅓% of an amount
\[ 33\tfrac{1}{3}\% \text{ of } 150 = 50 \]
Find one third of a number.
Find 66⅔% of an amount
\[ 66\tfrac{2}{3}\% \text{ of } 90 = 60 \]
Find two thirds of a number.
Timer (Optional)
Question