Answer:
The answer to you equation is 4
Step-by-step explanation:
Step 1: take the m and replace it 21 the multiply 21 and the numerator to get 21 over 3.
Step 2: divide 21 and 3 to get 7
Step 3: take the n and replace it with 12 then multiply 12 and 1 to get 12/2
Step 4: divide 12 and 2 to get 6
Step 5: then you do 7-1-2 which equals 4
