How do you simplify #(21-3)-(4+2)+(3+5)# using PEMDAS?

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Answer 1 · 2016-07-27T16:16:02

See explanation

We must solve in the PEMDAS order. There are three sets of parentheses, so let's solve for those:

#21-3=18#
#4+2=6#
#3+5=8#

We now have #18-6+8#

There's no exponents, multiplication, or division. Next up is addition:
#6+8=14#

#18-14#

From here it's simple subtraction: #18-14=4#

Answer 2 · 2016-08-01T23:58:12

#16#

There are 3 terms, each must simplify to a single answer which will be simplified in the LAST step.

#color(red)(21-3)color(blue)(-(4+2))color(magenta)(+(3+5))#

#color(red)(18)color(blue)(-(6))color(magenta)(+8) =18-6+8#

Note that this is NOT! #" "18 - (6 +8)#

We may not add in parentheses where we think they belong.

The additions are #+18 + 8# and the subtraction is #-6#

#18+8-6 = 16#