   SEARCH HOME Math Central Quandaries & Queries  Question from nakita, a student: can u explain the quinary subtraction... (3000) -(2342) all the numbers are in quinary number system Hi Nakita

I would think of this as an addition problem rather than a subtraction problem

What would you add to 23425 to get 30005?

Displaying it as we often do with an addition problem. Find the values of the questions marks if this addition is true in base 5.

 2 3 4 2 ? ? ? ? + _____ _____ _____ ____ 3 0 0 0

I can help you with the units digit. Since two plus three is five and five in base five is 105, the units digit of the difference between 30005 and 23425 is 3 and hence

 2 3 4 2 ? ? ? 3 + _____ _____ _____ ____ 3 0 0 0

If you learned the addition algorithm the way I did then you carry a 1 into the fives column. What is the value of the question mark in the fives column? What is the value of the question mark in the five squared column? What is the value of the question mark in the five cubed column?

You can use addition base five to check if your answer is correct.
Penny      Math Central is supported by the University of Regina and the Imperial Oil Foundation.