Explanation:
step 1. 40% of 700 means (40/100)(700)
step 2. (40/100)(700) = 280
step 3. mentally 7*4 = 28 so you know your answer has 28 in it
step 4. 40% of something is just less than half
step 5. half of 700 is 350. your answer is just less than that with a 28 in it. your answer is 280.