Rounding Up When You Should Round Down

(I am in the backseat, while my older brother is in the front with my mother. Her cell phone rings.)

Mom: “Hey, [older brother], will you answer that for me?”

Brother: “Sure, hello?”

(It’s my mother’s boss.)

Brother: “Yeah, my mom’s around. I told her to go on a diet for years, but she never listens.”

(You can hear through the phone how hard my mom thwacks my brother.)