C# code to clear textBox after result and re-enter

Question

Sir, I am doing a calculator program at the moment.

I have a problem with Re entering of number.

I like to have a code that clear textbox value while re-enter number after hitting "=" button(i.e suppose result is 32, when i hit number 1 again , i want to clear32 and to place 1 instead of.

please help me.