What mathematics do you teach or use in your work/life? Do you use technology? How do you use technology to help you?

I use Multimeter for measuring Current and Voltage because for the building services I need to check the loading of current before planning,design and installation the Light fitting and socket outlet where as for the measuring tape also needed to measure room size for number of air-condition.
I use telephones, mobile phone and email to receive and reply complain where as walkie-talkie to communicate with each other in the same department.