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DeWayfarer · 61-69, M
Nevaeh0081 · 36-40, F
pancakeslam · 41-45, M
ArishMell · 70-79, M
@Casheyane I made 7! = 3120 by mental arithmetic, to see if I could calculate it.
Then tested it with a calculator: 5040.
Ah! Oops!
I tried again, also by mental arithmetic, and realised I'd made a mistake with the second step. So, (7 X 6 =42, then X 5 = 210, then X 4 = 840). So far, quite easy.
Right, now 840 X 3, etc., mentally...
2540 (with difficulty), then X2 quite easily = 5040.
Yes, I had to type each answer as I went, as once I was into 4 digits and carrying hefty numbers the arithmetic became harder! (Exclamation-mark not factorial sign...)
Perhaps being an odd number multiplier of a big number, made the 'X3' step more difficult than the rest.
Then tested it with a calculator: 5040.
Ah! Oops!
I tried again, also by mental arithmetic, and realised I'd made a mistake with the second step. So, (7 X 6 =42, then X 5 = 210, then X 4 = 840). So far, quite easy.
Right, now 840 X 3, etc., mentally...
2540 (with difficulty), then X2 quite easily = 5040.
Yes, I had to type each answer as I went, as once I was into 4 digits and carrying hefty numbers the arithmetic became harder! (Exclamation-mark not factorial sign...)
Perhaps being an odd number multiplier of a big number, made the 'X3' step more difficult than the rest.