Calculation formula: 55x10+9x30=820/55x10-9x30=280 Button sequence: 55 X 10 M+ 9 X 30 M+ MRC/55 X 10 M+ 9 X 30 M- MRC. The desktop basic calculator is an essential tool in your life. The calculator with large screen & large buttons allows you to feel comfortable and see clearly.
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