Easy Maths

(1+6)x6/2 + (8+12)x5/2
=21+50
=71

Easy Maths

1+2+3+4+5+6+8+9+10+11+12=???

Careful, because you can do like this:

(1+12)x12/2

=13x12/2

=13x6

=78

No, no, no, because it is 1+2+3+4+5+6+8+9+10+11+12, no ''7''; in the middle. So, who can give me the correct answer? Please give the answer as fast as you can. The fastest and correct one could have 5+5 points ( 10 pionts ), so you must be quick.

1+2+3+4+5+6+8+9+10+11+12
=(1+12)*12/2-7
=13*12/2-7
=13*6-7
=78-7
=71

6(1+6)/2+50
=71

1+2+3+4+5+6+8+9+10+11+12
=(1+2+3+4+5+6)+(8+9+10+11+12)
=21+50
=71

1+2+3+4+5+6+8+9+10+11+12=???
Careful, because you can do like this:

(1+12)x12/2 - 7

=13x12/2 - 7

=13x6 - 7

=78 - 7

= 71

1+2+3+4+5+6+8+9+10+11+12
=(1+12)+(2+11)+(3+10)+(4+9)+(5+8)+6
=13+13+13+13+13+7
=13x4+7
=71//