To Multiply Any Number by 11.
Write the first right-hand figure, add the first and second, the second and third, and so on; then write the left-hand figure. Carry when necessary.
219434 × 11 = 2413774
Put down the right-hand figure 4. Then say, 4 and 3 are 7; then, 3 and 4 are 7; then, 4 and 9 are 13, put down 3 and carry 1; then, 9 and 1 and 1 are 11, put down the 1 and carry 1; then, 1 and 2 and 1 are 4; then write the left-hand figure 2. In multiplying small numbers, such as 24 by 11, write the sum of the two figures between the two figures, making 264, the required product.