Simple Math but............

smclean23 wrote:8 – [7 – (6 – 5 × 4 + 3) – 2 + 1] =
-11
-9
-1
13
21

Here is the explanation from MGMAT, my confusion is in CAPS....

The expression

8 – [7 – (6 – 5 × 4 + 3) – 2 + 1]

can be simplified as follows:

= 8 – [7 – (6 – 20 + 3) – 2 + 1] by first multiplying within the parentheses..... SHOULDN'T -20+3 BE SOLVED BEFORE 6-20?

= 8 – [7 – (-11) – 2 + 1] by performing the rest of the arithmetic in the inner parenthesis

= 8 – (7 + 11 – 2 + 1) by changing the sign of the -11 and converting operations (– to +). AGAIN, SHOULDN'T 7+11 AND -2+1 BE SOLVED FIRST?

= 8 – 17 by simplifying within the parentheses sequentially

= -9[/b]

I go with B as well

U need to know the PEDMAS rule for solving this ...i am sure u wud be aware of it...

8 – [7 – (6 – 5 × 4 + 3) – 2 + 1]

we need to solve the parentheses first

(6 – 5 × 4 + 3) = 6-20 +3 = -11.........................................a ( even if u solve -20 + 3 and then add 6..its the same affect...)


concentrate on inner bracket

[7 – (6 – 5 × 4 + 3) – 2 + 1]

using " a " w can re write this as

7-(-11) -2+1
18 -2+1 = 17...........................................................b ( AGAIN, SHOULDN'T 7+11 AND -2+1 BE SOLVED FIRST?....u can do so... iu will still land up with 18-1 = 17..its that u shud never loose focus of negative signs and be careful while dealing with them.....)

take the whole expression now

8 – [7 – (6 – 5 × 4 + 3) – 2 + 1]

rewrite using b

8- 17 = -9

Hope that helps.....

Thanks, but when you subtract 6 - -17, wouldn't that be 23 and not 11?