#Tip 1: Multiply big numbers by 11 or vice-versa in 5 seconds
11 * 36
>>>Step 1: Detach the unit digit and add it to the remaining figure.
i.e remove 6, add it to 3
3 + 6 = 9
>>>Step 2: Place the answer between the unit digit and the remaining figure
i.e put 9 between 3 and 6
= 396
That's the answer (Amazing!!!).
Still in doubt?
Let's try this
79 * 11
>>>Step 1: Detach the unit digit and add it to the remaining figure.
i.e remove 9, add it to 7
7 + 9 = 16
>>>Step 2: Place the unit digit of the answer between the unit digit and the remaining figure and add the other digit to the other figure.
i.e put 6 between 7 and 9 and add 1 to 7
= (7+1)69
= 869
That's the answer
>>> 7169
One more
====================
11 * 436
>>>Step 1: Detach the unit digit and add it to the remaining figure.
i.e remove 6, add it to 43
43 + 6 = 49
>>>Step 2: Place the unit digit of the answer between the unit digit and the remaining figure and add the other digit to the other figure.
i.e put 9 between 43 and 6 and add 4 to 43
= (43+4)96
= 4796
That's the answer
>>> 4796