Question 1123457
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this number = 8*5 + 7*8*5 = 40 + 280 = 320.


First addend  8*5  corresponds to the numbers having one of the digits {1, 3, 5, 7 ,9} as the last (ones) digit 
and 0 (zero) as the middle digit.


Second addend  7*8*5  corresponds to the numbers having one of the digits {1, 3, 5, 7 ,9} as the last (ones) digit; 
any different non-zero at the middle position and any different from these two non-zero digit at the most-left position.
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