The multiplication of two numbers spaced far from a power of 10
If you follow me, then you can solve all the problems below.
Only will one more modified process be added.
- The base shall be 5 X 10.
- You shall subtract 50 each from 48 and 53, which would be -2, +3.
- You shall position the numbers like the followed.
- On the left, you shall position the value of 48 + 3 or 53 + (-2) which is the diagonal summation and multiply the value by 5.
Don't forget to multiply the value by 5.
- On the right, you shall position the value of (-2) X 3.
The digits on the right must be equal to the number of zeros in base.
48 -2
53 +3
--------------------
51 |
X 5 |
--------------------
255 | -06
--------------------
255-1 | 10-06
--------------------
254 | 04
Do Exercise
- 7012 X 6998 = ?
Base : 7 X 1,000
7012 012
6998 -002
----------------------------
7010 |
X 7 |
----------------------------
49070 | -024
----------------------------
49070-1 | 1000-024
----------------------------
49069 | 976
ANOTHER TRICKS for 99, 999, 9999, · · ·
- You subtract 1 from the number other than 99, 999, 999, · · ·.
→ 16 - 1 = 15
- On the left, you shall position 15.
- You subtract this value from 99,999,999, · · ·.
→ 99 - 15 = 84
- On the right, you shall position 84.
The digits on the right must be equal to the number of nines in 99, 999, 9999, · · ·.
16
X 99
------------
15 | 84
Do Exercise
49625
X 99999
-------------------------
49624 | 50375
3452
X 99999
-------------------------
3452 | 96457
- 45237 X 999
→ If the digits of the number other than 99, 999, · · ·, is longer than 99, 999, · · ·
→ You convert 999 into (1000-1)
→ 45237 X (1000-1)
→ 45237000-45237
→ 45191763
