Main Question or Discussion Point
Without any rough work
why not?I don't think it's possible to multiply three numbers at the same time. The best you can do is to multiply two of them to get an intermediate product, and then multiply that one times the remaining number.
That's the first multiplication.1000000 a d g
That's the second multiplication.100000 a d h
That's third, and so on.10000 a d i
If I multiply two 1 digit numbers, I just use memorized multiplication tables. You could do that with multiplying 3 1 digit numbers also. Mulitiplying with at million is just a left shift.To add to what Borek said, to do the first multiplication (1000000 a d g) you would probably multiply a and d together, and then multiply that by g, and finally multiply that by 1000000. Multiplication is a binary operation, meaning that it operates on two numbers. That's what I was talking about in post #6.
To multiply three numbers, you can use the fact that multiplication is associative (i.e., (ab)c = a(bc)) to multiply a pair of the numbers and then multiply that product by the third.