A great deal of studies have proven the latest conventional wisdom: multitasking is a myth.
If it takes you 5 minutes to focus on and complete task A and 10 minutes to focus on and complete task B, trying to do them both at the same time instead of completing one and then completing the other guarantees it will take you longer than 15 minutes.
For a bill of 15.73, move the decimal over once to the left. You get 1.57. (drop the 3). That's ten percent. Let's say it's 1.50.
Half of that is 75¢. Half of ten percent is five percent so now you have ten percent and five percent. Add them together to get 15%: 1.50 + 0.75 = $2.25 = 15% tip.
20% is even easier. If ten percent is 1.50, twenty percent is double that: $3.00
Am I the only person who fucking hates the forced laughter tracks on all these videos. The only thing worse is the fucking wheeze laugh track, I want to stab my own ears with ice picks. It's the aural version of being told THIS IS FUNNY. YOU SHOULD THINK THIS IS FUNNY. SEE HOW THIS IS FUNNY.
"Something you have" is absolutely not equivalent to "something you know"
You are completely unable to enter this conversation, but you think you're the smartest one in the room.
I bet you're insufferable.