This is a better deal than the second option where each pack costs more than 200. Apart from distributive property if your maths is for working in a shop you can use counting up. For just one example out of many simple mental math tricks you can get a 20-sided die and give it a couple of rolls.
Mental math wont only help improve your business-decision making ability it will help you save time if you estimate the activitys duration better and money when a shopping or restaurant bill is miscalculated.
Get this full course at. The ability to quickly perform mental calculations offers advantages in certain circumstances. Encourage children to memorize the doubles from 1 1 through 9 9. Before giving students a mental math problem instruct them to stand up if the answer is greater than.