200
Portions of quantities can be represented as percentages and decimals, which can help solve different types of questions.
Multiplying Decimals
To find any percent of a quantity, you can multiply the quantity by the percentage as a decimal. We can convert percentages to decimals easily. By moving the decimal point 2 places to the left, we can change 40% into a decimal. So, 40% is equal to 0.4. Now, multiply this by 500.
So, Leo has put together 200 pieces.
Multiples of 10
Since 40% is a multiple of 10, we can solve using another method. It is easy to find 10% of any quantity, just move the decimal point 1 place to the left. So, 10% of 500 is 50.
Then, since 40 is 4 times 10, we can say that 40% of 500 is 4 times 10% of 500.
This proves that Leo has done 200 pieces.
