100% --- $79.99
1% --- $(79.99÷100) = $0.7999
20% off means 100% - 20% = 80%
80% --- $0.7999×80 = $63.992
Leave it to the nearest cent: $63.99 ---- Answer!
If you need further clarifications, leave a comment down below! I'll try my best to help you. :)
