127
| Example II.—8 multiplied by 8: | |
| 10 — 8 = | 2 |
| 10 — 8 = | 2 |
| 64 |
10 minus 8, equals 2, the remainder from the multiplicand,
10 minus 8, equals 2 ditto multiplier.
Multiply one by the other, equals 4, the unit figure.
Subtract the lower 2 from the upper 8 leaves 6, the tens figure.
| Example III.—9 times 6: | ||
| 10 — 9 = | 1 | |
| 10 — 6 = | 4 | - 1 × 4 = 4 |
| 54 |
To perform the operations in the mind of multiplying figures beyond 12, without having recourse to the usual mode of working them on paper or slate, may be, in some cases, desirable; a few examples are given, in hopes that some general rule may be deduced, to render them still more simple.
—In figures between 12 and 20, the multiplier must be added to the right-hand or unit figure of the multiplicand, to which result join a cipher, then multiply the unit of the multiplicand, by the unit figure of the multiplier, and add such product to the sum gained by the first operation; as in this example.
18 multiplied by 15—
| 15 | Add 18 to 5 makes 23, to which join a cipher, = | 230 | |
| 18 | Multiply the 5 of 15, by the 8 of 18, equals | 40 | |
| 270 | Which added to 230 is | 270 |
