← All MathIsland labs+10%VAT Lab Browse all labs →
Add 10%, then subtract 10% — you don't get back
Why does this exist?
To recover the pre-tax price you must divide, not subtract. (Korea's 10% VAT as the running example.)
🔬 The interactive lab is live — currently in Korean
Sliders and simulations speak every language. Most visitors can follow the experiment even without reading Korean — and a full English version of this lab is on the way.
Try the interactive lab →