Talk:Subtraction without borrowing

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• Only the basic algorithm for subtraction without borrowing is described here. In practice it is not always necessary to reduce by 1 the leftmost digit of the minuend, which is greater than the corresponding digit of the subtrahend. For example, consider

     65435
   - 23194
     -----

In this case it is sufficient to change the third digit of the minuend from a 4 to a 3 and then the 35 to 99. The new minuend is then 65399 and the difference is 65435 – 65399 = 36, which equals to 35 + 1.

• I have heard from an elementary-school teacher that this method is the standard subtraction method that is taught in Portugal's elementary schools. So far I was unable to corroborate her information. I will appreciate it very much, if anyone, who knows how subtraction is or was taught in Portuguese schools, would contribute his or her knowledge here.

UriGeva 02:02, 27 November 2005 (UTC)