Arithmetic
Splitting an amount in a ratio
Divide the total by the sum of the parts, then allocate each part's share.
The Formula
share = T x part / (a + b)
Divide the total by the sum of the parts, then allocate each part's share.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| share | Individual share | units of T | The amount going to one part. |
| T | Total | units | The whole amount being divided. |
| a | First part | none | The first ratio term. |
| b | Second part | none | The second ratio term. |
What Each Symbol Means
shareunits of T
Individual share
The amount going to one part.
Tunits
Total
The whole amount being divided.
anone
First part
The first ratio term.
bnone
Second part
The second ratio term.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate a ratio page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate A Ratio, filed under Math. Every number the guide produces comes from substituting into this one line.