The first one, Xiaofen Wang, who is a waitress, says there is a lot of math going on during her job. She uses math in taking orders, in adding up orders, and finding a table with the right amount of chairs for the guests. There is also tax add to the orders. She says she uses subtraction also when, for example, a certain number of customers come, but some don t come to eat. Then she would have to subtract some amount from the original total, to find the correct one.
Multiplication comes in handy too.
Like, for example, when several people order dishes that have the price, she must multiply the price of one dish by the number of dishes ordered. Also, when she figures out tax, she needs to multiply. Sometimes, she uses rounding to first estimate the price, but usually adding a the actual numbers is a better way, although it is a slower process. Also, when she pour water into the glass, she has to estimate how much to pour in. Sometimes she uses percentage too.