A numerical expression is evaluated as shown. 20 + (8 x 9 + 18) ÷ 10 x 4 Step 1: 20 + (72 + 18) ÷ 10 x 4 Step 2: 20 + 90 ÷ 10 x 4 Step 3: 110 ÷ 10 x 4 Step 4: 11 x 4 In which step does the mistake first appear?