3 Digit Number - Maths Investigations

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CWK1

3 Digit Number

Take any 3 digit number, write down all possible numbers that can be made with the three digits, add them up, divide the total by the sum of the 3 digits. Investigate.

If All Digits Are Different : -

  123                        456                        789

  132                        465                        798

  213                        546                        879

  231                        564                        897

  321                        654                        987

+312                          +645                          +978

1332 ÷ 24=222        3330 ÷ 15=222        5328 ÷ 24=222

  147                        258                        369

  174                        285                        396

  471                        528                        639

  417                        582                        693

  741                        825                        936

+714 _                          +852                          +963

  2664 ÷ 12=222        3330 ÷ 15=222        3996 ÷ 18=222

It seems that when all 3 digits are different the answer to the problem is 222.

Can I use Algebra to explain this?

abc=100a+10b+c

acb=100a+10c+b

bac=100b+10a+c

bca=100b+10c+a

cba=100c+10b+a

+cab=100c+10a+b

Join now!

                      222a+222b+222c = 222(a+b+c)

                                             a+b+c

=222

What if 2 of the 3 digits are the same?

If 2 digits are the same : -

  223                        334                        566

  322                        343                        656

+232                          +433                          +665

  777 ÷ 7=111                1110 ÷ 10=111        1887 ÷ 17=111

  224                        559                        772

  242                        595                        727

+422                          +955                          +277

  888 ÷ 8=111                2109 ÷19=111                1776 ÷ 16=111

It seems that when 2 of the 3 digits are ...

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