@pinkpencilmath [1]

Do you guys know this?!?! 🤯 #viralmath [2] #mathtricks [3] #pinkpencil [4] #math [5] #fyp [6] #percentages [7] #mathhelp [8] #mathtutor [9] #brainteaser [10] #percent [11] #fractions [12] #maths [13]

♬ Spongebob Tomfoolery - Dante9k Remix - David Snell [14]

I've never been a maths person, so when I found this viral maths secret on TikTok [15] that made sense to me and my right-sided brain, my mind was blown. Essentially it helps with percentages — and in everyday life, that means finances and, most commonly, tipping (see a tipping etiquette guide here [16]).

While I've always used the rule "two dollars for every 10," on top of other rules like moving the decimal point from one place to the left, this one is another to add to the lineup. Essentially, the secret to percentages is that they can be reversed, so if you're looking for 16 percent of 50 you can do 50 percent of 16 which equals eight. Surprising, right? @PinkPencilMath [17], a mechanical engineer, explains it best in her TikTok video — so make sure to watch and give it a try the next time you're out to eat!