math! first one to answer get 10 points?
815705
$310\n\n\n50 x 8 = 400\n\n100 x 23 = 2300\n\n400 x .20 = $80\n2300 x .10 = $230\n\n80 + 230 = $310
167144
4 6 1 9 2 3 8 5 7 \n7 8 3 5 1 6 9 4 2 \n9 5 2 7 8 4 1 3 6 \n8 4 9 6 3 5 7 2 1 \n6 1 5 2 9 7 3 8 4 \n2 3 7 8 4 1 5 6 9 \n1 2 4 3 5 9 6 7 8 \n3 9 6 4 7 8 2 1 5 \n5 7 8 1 6 2 4 9 3\n\n\nsolved in 9 minutes 28 seconds
12336
Try the BBC's Maths series and MathsFile as well as Math.com (see links below)
609300
This is more of a word problem or a riddle than a math problem.\n\nThe answer is 7 (SEVEN).  Remove its first letter and it becomes EVEN!
245176
u*(u-2)+v*(u-2)\n(u+v)*(u-2)
912865
bring the a's to one side... u then get 9a = 27 ... divide and answer is a = 3
771168
1= B\n2= A\n3= D\n4= D\n5= D\n6= C
144487
the answer is exponents.
96233
+5,+12, -5, -12, +3.3
521593
Forty of course.\n\n=D
674498
1+1=2. That's it. The answer for everything else would be simply 42
263164
I won 10 points!\n\nThis is pretty easy. Try to stump me with harder ones.
972447
8,6.12,18,10,1,4,21,8,12,7,15
4519
(4/3)*pi*r^3\n\n[four thirds pi r cubed]\n\ngood luck!
465985
1 - D\n2 - B\n3 - C\n4 - C
750837
1--d\n2--a\n3--b\n4--a
1076304
(1) 1.3\n(4) 4\n(5) Right\n(6) 0\n(7) 0\n(8)0\n(9)12