| £. | s. | d. |
| 6 | 15 | 5 |
| 20 | ||
| 135 | ||
| 12 | ||
| 1625 | Answer. | |
To convert from a lower to a higher denomination.
Rule.—Divide the given number by as many of the lower denomination as are required to make one of the greater.[41] Should there be any remainder, it will be of the same denomination as the dividend.
Example.—Convert 1625 pence into pounds, shillings, and pence.
| 12 ) | 1625 | pence | |
| 20 ) | 135 | 5 | |
| £6 | 15s. | 5d. Answer. | |
THE RULE OF THREE, OR SIMPLE PROPORTION.
It is called the Rule of Three because three numbers are given to find a fourth. It is also called Simple Proportion, because the 1st term bears the same proportion to the 2nd, as the 3rd does to the 4th. Of the three given numbers, two of them are always of the same kind, or name, and are to be the 1st, and 2nd terms of the question; the 3rd number is always of the same name, or kind as the 4th, or answer sought; and in stating the question it is always to be made the 3rd term. If the answer will be greater than the 3rd term, place the least of the other two given quantities for the 1st term; but if the answer will be less than the 3rd term, put the greater of the two numbers, or quantities, for the 1st term.
Rule.—State the question according to the above directions, and multiply the 2nd and 3rd terms together, and divide this product by the 1st, for the 4th term, or answer sought.
If the 1st and 2nd terms are not of the same denomination, they must be reduced to it; and if the third term is a compound number, it must be reduced to its lowest denomination before the multiplication, or division of the term takes place.