Using only the digits 0,1,2,3, write down all
possible three digit numbers with sum of digits 3,
allowing numbers to begin with 0, in order from
largest to smallest:
300
210
201
120
111
102
030
021
012
003
in each, use the digits of each 3-digit number
in the order they appear as exponents of
a, b, and c respectively, as this scheme shows:
300 --> a3b0c0 = a³
210 --> a2b1c0 = a²b
201 --> a2b0c1 = a²c
120 --> a1b2c0 = ab²
111 --> a1b1c1 = abc
102 --> a1b0c2 = ac²
030 --> a0b3c0 = b³
021 --> a0b2c1 = b²c
012 --> a0b1c2 = bc²
003 --> a0b0c3 = c³
Rewrite the dividend a³+b³+c³-3abc putting in zero
place-holders for each of those not represented in
that dividend, in that order. That is, the dividend
becomes:
a³ + 0a²b + 0a²c + 0ab² - 3abc + 0ac² + b³ + 0b²c + 0bc² + c³
So we start with this:
_______________________________________________________________
a + b + c)a³ + 0a²b + 0a²c + 0ab² - 3abc + 0ac² + b³ + 0b²c + 0bc² + c³
Then we divide a³ by a, getting a², and we write that as the 1st term of the quotient.
a²
a + b + c)a³ + 0a²b + 0a²c + 0ab² - 3abc + 0ac² + b³ + 0b²c + 0bc² + c³
Then we multiply that by each term of the divisor and place each product
under the term that it is like, and draw a line under it:
a²
a + b + c)a³ + 0a²b + 0a²c + 0ab² - 3abc + 0ac² + b³ + 0b²c + 0bc² + c³
a³ + a²b + a²c
Then we subtract and bring EVERY term down
a²
a + b + c)a³ + 0a²b + 0a²c + 0ab² - 3abc + 0ac² + b³ + 0b²c + 0bc² + c³
a³ + a²b + a²c
-a²b - a²c + 0ab² - 3abc + 0ac² + b³ + 0b²c + 0bc² + c³
Then we divide -a²b by a, getting -ab, and we write that as the 2nd term of the quotient:
a² - ab
a + b + c)a³ + 0a²b + 0a²c + 0ab² - 3abc + 0ac² + b³ + 0b²c + 0bc² + c³
a³ + a²b + a²c
-a²b - a²c + 0ab² - 3abc + 0ac² + b³ + 0b²c + 0bc² + c³
Then we multiply that by each term of the divisor and place each product
under the term that it is like, and draw a line under it, subtract and bring
EVERY term down:
a² - ab
a + b + c)a³ + 0a²b + 0a²c + 0ab² - 3abc + 0ac² + b³ + 0b²c + 0bc² + c³
a³ + a²b + a²c
-a²b - a²c + 0ab² - 3abc + 0ac² + b³ + 0b²c + 0bc² + c³
-a²b - ab² - abc
-a²c + ab² - 2abc + 0ac² + b³ + 0b²c + 0bc² + c³
Keep doing that, and end up with this:
a² - ab - ac + b² - bc + c²
a + b + c)a³ + 0a²b + 0a²c + 0ab² - 3abc + 0ac² + b³ + 0b²c + 0bc² + c³
a³ + a²b + a²c
-a²b - a²c + 0ab² - 3abc + 0ac² + b³ + 0b²c + 0bc² + c³
-a²b - ab² - abc
-a²c + ab² - 2abc + 0ac² + b³ + 0b²c + 0bc² + c³
-a²c - abc - ac²
ab² - abc + ac² + b³ + 0b²c + 0bc² + c³
ab² + b³ + b²c
- abc + ac² - 0b³ - b²c + 0bc² + c³
- abc - b²c - bc²
ac² - 0b³ + 0b²c + bc² + c³
ac² + bc² + c³
0
So the answer is: a² - ab - ac + b² - bc + c²
Edwin