Mathematics Made Simple Part 4

Please go to Mathematics Made Simple and Mathematics Made Simple part 2 & 3 before you read this blog because this is one step further.

Another brain training session again, I do hope that everybody who have read the earlier session find it interesting and helpful.

Let’s go straight to the point without further ado.

Add 11-40. Please give me the answer immediately without having to use calculator or computer. The answer is 765. This time we have to use another formula to get the answer immediately.

Formula:

N = number of digit, in this case 30 digits
A = number of digit excluded from the calculation, ie 10 digits
T = last digits in the calculation, ie 40

N/2 (T+A+1)
= 30/2 (40+10+1)
= 15(51)
= 765

Add 45-90. Again no calculator or computer is allowed. Please give me the answer immediately. The answer is 3105. You may use the computer to test it later.

N = number of digit, in this case 46 digits.
A = number of digit excluded from the calculation, ie 44 digits
T = last digits in the calculation, ie 90

N/2 (T+A+1)
= 46/2 (90+44+1)
= 23(135)
= 3105

I create this technique after I learned the simple technique from my ex boss aged 70 when I was working for his company.

Stay tuned to this blog, if you want to challenge yourself to more difficult level of mathematics made simple in my next session.

Happy learning!