oemahmatematika.com

Rule; the first digit of the given number minus 1 is the first digit of the answer. the second digit of the answer is obtained by subtracting the first digit of the given numbeer from 9 and adding it to the second digit of the given number. continue this process by subtracting each digit in the given number from 9 and adding to the result the next digit to its right. stop this procedure after the tens digit of the answer is obtained by subtracting the units digit of the given number from 10. in each case, if the sum is a two-digit number, record the units digit and carry the tens digit to the precending answer digit.

multiply 7,149 by 9

the first digit of the given number minus 1 is the first digit of the answer.

7-1 = 6

the second digit of the answer is minus 9 the first digit of the given  number plus the second digit of the given number.

9-7 =2; 2 + 1= 3

we now have first two digits of the answer (at least tentatively).

63

to obtain the third digit of the answer, subtract the second digit of the given number from 9 and add result to the third digit of the given number.

9-1=8; 8+4=12

here the result is a two digit number. the units digit is record as part of the answer, and the ens digit is carried and aded to the 3 previously determined. the first tree digits of the answer are now

6 4 2 the tens digit and the units of the given number are used to obtain the tens digit of the answer.

9-4=5; 5+9=14

record the 4, carry the 1, and add it to the 2 previously determined. the units digit of the answer is merely 10 minus the units digit of the given number.10-9=1

the product is therefore

7,149 x 9 = 64,341 answer