It’s a comedy made in the last few years about two guys/buddies from the 80s or 90s that time travel to the future. Once they’re in the future they see people standing around, holding their cell phones. One guy asks his buddy why everyone has their calculators out. They both think people are holding calculators because they traveled from a time when cell phones didn’t exist.
Quote from a review for the movie from the internet:
“like when Reeves and Harris mistake cell phones for calculators and think they mistakenly walked into a math convention.”
You can read the complete review where the above quote is from here: