Theory
A ratio divides a total into fixed parts.
First add the ratio parts. Then you know how many equal parts the total consists of.
Divide the total by that number of parts. Then multiply by each part of the ratio.
- Add the ratio partsAdd the ratio parts.
When adding, you combine two amounts.
You can count from left to right, but with larger numbers it is often easier to make a round number first.
If you use part of the second number to fill up the first number, then after that you only need to add the rest.
- See if you can add on in a smart wayWith larger numbers, you can often make a round number first.
- Add the restThen add what is left.
- See if you can add on in a smart way
- Calculate the value of 1 partDivide the total by the number of ratio parts.
Dividing means sharing an amount fairly or seeing how many equal groups fit into it.
The first number is the total amount. The second number tells you what you divide by.
Always check whether the division works out exactly. If it does not, you get a decimal number or fraction as the answer.
- Calculate the first partMultiply the value of 1 part by the left ratio part.
You use multiplication with equal groups.
A × B means that you take the same amount B, A times.Instead of adding again and again, you calculate the product all at once.
- Calculate the second partMultiply the value of 1 part by the right ratio part.
You use multiplication with equal groups.
A × B means that you take the same amount B, A times.Instead of adding again and again, you calculate the product all at once.
- Add the ratio parts2 + 3 = 5.
- See if you can add on in a smart wayGebruik direct optellen bij 2 + 3.
- Add the rest2 + 3 = 5.
- See if you can add on in a smart way
- Calculate the value of 1 part60 ÷ 5 = 12.
- Calculate the first part12 × 2 = 24.
- Calculate the second part12 × 3 = 36.