100 Square Calc: Add & Mul

10x10 simple 100 square calculation.
It supports addition and multiplication, and can record time on a graph.
Improves calculation skills and mental arithmetic skills, and helps train the brain.

Functions/Features
- Addition 100 Squares Calculation
- Multiplication 100 Squares Calculation
- Smooth numeric input
- Measure your time
- Record in graph
- Display personal best/average time
- Customization (dark mode, theme colors)
- Simple design compliant with Material Design