Quicker way? Hmm...
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When you multiply 11 by something, it basically equals to \(\text{that number} \times 10 + \text{that number}\).
So it is that number plus that number 'shifted' 1 place to left.
So if that number is 121, it would look something like this:
121
+121
So it is \(\text{(hundreds)} + \text{(tens + hundreds)} + \text{(ones + tens)} + \text{(ones)}\), which is the same as Pascal's triangle!
Then just clear up the mess and you get a number.
