Question

practical uses of maths

Answer 1

counting back change after purchasing
how much  $1 trillion dollars 
computing mentally how much money is to leave as a tip in restaurant
using world clock to determine the time required to fly from one city to another across time zones

Answer 2

practical uses of maths:
# science
# technology
# civil site
# economics
# business
# commerce
# computer design
# functioning
# counting things 
# buying in grocery
# measuring things
 
i cant list out all as its uses are endless......