How do you simplify 21+6+9? Algebra Expressions, Equations, and Functions PEMDAS 1 Answer Koko S. Apr 15, 2018 36 Explanation: 21+9=30, 30+6=36 Answer link Related questions What is PEMDAS? How do you use PEMDAS? How do you use order of operations to simplify 3(7−2)−8? What are common mistakes students make with PEMDAS? How do you evaluate the expression 5[8+(3−1)]−2? How do you simplify the expression 4(30−(3+1)2)? How do you evaluate the expression x4+x if x=2? Is it okay to add first before subtracting in 4−6+3? How do you simplify (−3)2+12⋅5? How do you simplify (4−2)3−4⋅8+21÷3? See all questions in PEMDAS Impact of this question 3151 views around the world You can reuse this answer Creative Commons License