how many times can you get the sum of 12 using the numbers 1, 2, 3, 4, 5, 6, 7, 8, and 9? (oh and by the way you can't use the sam enumber twice in any one combinations.)
2007-05-31 13:55:25 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
9 + 3
9 + 2 + 1
8 + 4
8 + 3 + 1
7 + 5
7 + 4 + 1
7 + 3 + 2
6 + 5 + 1
6 + 4 + 2
6 + 3 + 2 + 1
5 + 4 + 3
5 + 4 + 2 + 1
All combinations that start with 4, 3, 2 or 1 have to use numbers larger than 4 so they will appear in the above list.
Therefore the number of ways of getting 12 adding numbers in the set is 12. Notice the pattern to decompose a number into sums of numbers less than it, that I used in generating the list.
2007-05-31 14:05:42 · answer #1 · answered by Bazz 4 · 0⤊ 1⤋
1 + 2 + 3 + 6
1 + 2 + 4 + 5
1 + 2 + 9
1 + 3 + 8
1 + 4 + 7
1 + 5 + 6
2 + 3 + 7
2 + 4 + 6
3 + 4 + 5
3 + 9
4 + 8
5 + 7
I found 12 ways to do it.
2007-05-31 21:35:09 · answer #2 · answered by Don E Knows 6 · 0⤊ 0⤋
1+2+3+6
1+3+2+6
2+1+3+6
2+3+1+6
3+1+2+6
3+2+1+6
1+2+6+3
2+1+6+3
3+1+6+2
1+3+6+2
2+3+6+1
3+2+6+1
1+6+2+3
2+6+1+3
3+6+1+2
1+6+3+2
2+6+3+1
3+6+2+1
6+1+2+3
6+1+3+2
6+2+1+3
6+2+3+1
6+3+1+2
6+3+2+1
9+3
9+2+1
8+4
8+3+1
7+5
7+4+1
7+3+2
6+6
6+5+1
6+4+2
5+4+3
24 ways for the 4 digit combo (as shown)=24
6 ways diferent orders for all 7 of the 3 digit combos each=42
2 ways for all 4 2 digit combos except (6+6) = 6
1 way for (6+6) =1
That makes 73 ways...
Anyone disagree?
2007-05-31 21:09:47 · answer #3 · answered by . 2 · 0⤊ 0⤋
9 + 3
8+4
7+5
93 + (-81)
94 + (-82)
95 + (-83)
96 + (-84)
97 + (-85)
86 + (-74)
85 + (-73)
84 + (-72)
83 + (-71)
75 + (-63)
74 + (-62)
73 + (-61)
69 + (-57)
64 + (-52)
63 + (-51)
59 + (-47)
58 + (-46)
54 + (-42)
53 + (-41)
49 + (-37)
48 + (-36)
47 + (-35)
46 + (-34)
43 + (-31)
39 + (-27)
38 + (-26)
37 + (-25)
36 + (-24)
35 + (-23)
29 + (-17)
28 + (-16)
27 + (-15)
26 + (-14)
25 + (-13)
24 + (-12)
21 + (-9)
19 + (-7)
18 + (-6)
17 + (-5)
16 + (-4)
15 + (-3)
14 + (-2)
2007-05-31 21:20:21 · answer #4 · answered by jacobandalex 2 · 0⤊ 0⤋
(9+3)
(9+2+1)
(8+4)
(8+3+1)
(7+5)
(7+4+1)
(7+3+2)
(6+ 3+2+1)
(6+5+1)
(6+4+2)
(5+4+3)
(5+4+2+1)
i get 12 combinations
2007-05-31 21:13:08 · answer #5 · answered by ironduke8159 7 · 0⤊ 0⤋
7
2007-05-31 21:06:31 · answer #6 · answered by math geek 3 · 0⤊ 1⤋
You can only sum up the #12 three times using 1-9.
2007-05-31 21:11:40 · answer #7 · answered by lusani j aka LJ 1 · 0⤊ 1⤋
1,2,3,6
9,3
8,4
7,5
1,3,8
1,5,6
1,4,7
1,2,9
2,3,7
2,4,6
3,4,5
i'm pretty sure that's it
2007-05-31 21:00:46 · answer #8 · answered by Anonymous · 0⤊ 1⤋