Hi All,
For some among us, it might be a cakewalk, those folks who attempted GMAT or CAT, etc., but still, it is nice and pretty, so sending it to you all.
Some tips for multiplication with 9, 11, 12, 13:
With 9: -
Place 0 on the right side of the number, then subtract the actual number from this. For example -
2345 * 9 = ?
Step 1 - place 0 on the right - 23450
Step 2 - Subtract the actual number - 2345
21105
With - 11: -
Ex: - 4987 * 11 = ?
Step 1 - place 0 on the left of the digit, like 04987 in our case.
Step 2 - multiply the rightmost digits of both numbers, i.e., (7 * 1). If carry comes, then carry it over to the next term.
04987
11
54857
Step 3 - now add the ten-digit number with the unit digit number (8 + 7 = 15), write 5 and carry over 1.
Step 4 - now add the hundred-digit number with the ten-digit number (9 + 8 = 17 + 1 (carryover from the previous step) = 18).
Similarly, proceed up to the leftmost digit, so we get 54857.
With 12: -
It is similar to the method used for 11.
The only difference is in this we have to multiply by 2 then add to the previous digit.
For example: 4987 * 12 = ?
04987
12
59844
Step 2 - 7 * 2 = 14, write 4 and carry over 1.
Step 3 - 8 * 2 + 7 = 23 + 1 = 24, write 4 and carry over 2.
Step 4 - 9 * 2 + 8 = 26 + 2 = 28, write 8, 2 carry over.
Step 5 - 4 * 2 + 9 = 17 + 2 = 19, write 9 and carry on 1.
Step 6 - 0 * 2 + 4 = 4 + 1 = 5.
With 13 - it is similar to 12 but instead of multiplying by 2, here we have to multiply it by 3.
Enjoyable, EASY??????????????
Thanks,
Bala
For some among us, it might be a cakewalk, those folks who attempted GMAT or CAT, etc., but still, it is nice and pretty, so sending it to you all.
Some tips for multiplication with 9, 11, 12, 13:
With 9: -
Place 0 on the right side of the number, then subtract the actual number from this. For example -
2345 * 9 = ?
Step 1 - place 0 on the right - 23450
Step 2 - Subtract the actual number - 2345
21105
With - 11: -
Ex: - 4987 * 11 = ?
Step 1 - place 0 on the left of the digit, like 04987 in our case.
Step 2 - multiply the rightmost digits of both numbers, i.e., (7 * 1). If carry comes, then carry it over to the next term.
04987
11
54857
Step 3 - now add the ten-digit number with the unit digit number (8 + 7 = 15), write 5 and carry over 1.
Step 4 - now add the hundred-digit number with the ten-digit number (9 + 8 = 17 + 1 (carryover from the previous step) = 18).
Similarly, proceed up to the leftmost digit, so we get 54857.
With 12: -
It is similar to the method used for 11.
The only difference is in this we have to multiply by 2 then add to the previous digit.
For example: 4987 * 12 = ?
04987
12
59844
Step 2 - 7 * 2 = 14, write 4 and carry over 1.
Step 3 - 8 * 2 + 7 = 23 + 1 = 24, write 4 and carry over 2.
Step 4 - 9 * 2 + 8 = 26 + 2 = 28, write 8, 2 carry over.
Step 5 - 4 * 2 + 9 = 17 + 2 = 19, write 9 and carry on 1.
Step 6 - 0 * 2 + 4 = 4 + 1 = 5.
With 13 - it is similar to 12 but instead of multiplying by 2, here we have to multiply it by 3.
Enjoyable, EASY??????????????
Thanks,
Bala