**The standard multi-digit
subtraction procedure (algorithm) that is taught to most, if not all, students
requires that the student is capable of subtracting any single-digit number
from any number in the range of 10 to 19. For the student must be able
to "borrow" a "ten" from the digit to the left of the current one. In other
words, the strongest demand on the student's mathematical skill is the
ability to mentally subtract any single digit number from any number between
10 and 19, inclusively.**

**For the students
who struggle with this requirement this new procedure provides an easier
alternative. It required that the strongest subtraction skill is the ability
to subtract any single-digit number from any single-digit number. It also
requires the ability to add multi-digit numbers, a skill that students
are assumed to possess before they are taught multi-digit subtraction.**

**This procedure does
not employ borrowing. Instead it replaces the source number with a substitute
from which the subtraction can proceed without borrowing. After the subtraction
is finished, the result is adjusted by adding the number that was used
to generate the substitute source number.**

**A bonus of this
procedure is the fact the actual subtraction can proceed from left to right
just as traditionally it is done from right to left. In fact, as long as
digits are subtracted in their columns and subtraction is carried out in
each and every column, the order is no longer relevant.**

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Last Update: Sep. 1, 2008