To find the missing digits in a long division.

divisibilityelementary-number-theory

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It is given that the leading digit of every number in the division structure is nonzero.

I am not getting how to find all the missing digits given only one digit from the quotient and given that the reminder is $0$.

Any help on how to proceed will be helpful.


Source: Homework Assignment.


This is what I got.

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Best Answer

Probably the most powerful piece of information comes from the 7 in the quotient. If you look down from there, you see that 7 times the three-digit divisor gives a three-digit number. That means that the divisor has to be between 100 and 142 (since 7x143 = 1001), and so its first digit must be 1.

From that, you can see that a couple of the products are 4 digits, so they must be multiplying the divisor by 8 or 9 - but even 142x9 = 1278, so the first of those four digits must be a 1. You can then use that to gain more information about the divisor, and also about what digits could go in each place.

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