Filling in the ratio table
You learn to fill in a ratio table, even when it does not work in one step.
How to work it out
- Find how you get from the first number on top to the last one.
- If that does not work in one step, go to 1 first: divide by the first number.
- Then go from 1 to the number you want: multiply by that number.
- Do exactly the same on the top and underneath.
2
4
6
12
A worked example
Top: 2 and 4. Bottom: 6 and ?
- On top you go from 2 to 4: that is times 2.
- Do times 2 underneath too: 6 × 2 = 12.
- It goes with 12.
More examples
Top: 2 and 5. Bottom: 6 and ?
- You cannot get from 2 to 5 in one step.
- Go to 1 first: divide the top and the bottom by 2, so underneath 6 ÷ 2 = 3.
- Then go to 5: multiply by 5, so underneath 3 × 5 = 15.
- It goes with 15.
2
6
5
15
Top: 4 and 6. Bottom: 10 and ?
- Go to 1 first: divide by 4, so underneath 10 ÷ 4 = 2.5.
- Then go to 6: multiply by 6, so underneath 2.5 × 6 = 15.
- It goes with 15.
4
10
6
15
Watch out
You add the same on top and underneath: 2 to 5 is 3 more, so underneath 6 + 3 = 9.
In a ratio table you multiply or divide. Go via 1 if it does not work in one step.
You only divide on top and not underneath.
Do every step in both rows. Write the middle step in the empty box.
Tips
- If it does not work in one step, go to 1 first.
Why it works
The top and the bottom belong together, so whatever you do on top you must do underneath too. Sometimes there is no easy step from one number to the next. Then you go via 1: first divide, then multiply, and the top and the bottom stay in step.