Dividing by half is the same as multiplying by 2. 40 / 0.5 = 80. Then, 80 + 10 = 90. A common mistake is to divide by 2 (40/2=20), which would lead to 30.
To solve this problem, let's break it down step by step:
Divide 40 by half: When we divide by half, it is equivalent to multiplying by 2. So, dividing 40 by half is the same as multiplying 40 by 2, which gives us 80.