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How many 4 digit numbers are there that don't have a five in them. [with in the range of 1000-9999 Also what is short test method.

Note by Mardokay Mosazghi
2 years, 10 months ago

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The thousands digit can only be 1,2,3,4,6,7,8,9 = 8 digits. Hundreds digits: 9 Tens digits: 9 Ones digit: 9 8 x 9 x 9 x 9 = 5832. I think... Tan Wee Kean · 2 years, 10 months ago

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the question can be stated in another way like this.."how many numbers are divisible by five within 1000-9999" if so, then just use arithmetic progression to get how many numbers are divisible by five..thus, 9995=1005+(n-1)(5), n=1799, then answer is.. 9000-1799=7201 Roland Casuga · 2 years, 10 months ago

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@Roland Casuga What about 5554? It's not divisible by 5, yet still contain 5 in it. Samuraiwarm Tsunayoshi · 2 years, 10 months ago

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