what are the formula to make a scientific calculator using visual basic??
Formula for Sin, Int, Mod, And, Or, Lsh??

There isn't a "formula" to make a scientific calculator. You have to write an entire program to do that.

If you were to write a four-function calculator (certainly not anywhere near a "scientific calculator"), you could drop four buttons on a form. Label the buttons "+", "-", "*", and "/". Put a text box in the area for an "accumulator". Drop ten additional buttons on the form and label them "0", "1", "2", "3", "4", "5", "6", "7", "8", "9". Double-click on each of the buttons to create "handlers" for each "on-click" event. Write code to add the numerals to the accumulator or to add, subtract, multiply, divide.

If you want a scientific calculator, you must also add buttons or handlers for the features you want (trigonometry, roots, powers, etc).

Sin is used to generate the sine function of an angle.
Int takes a real number and truncates it so as to remove the fractional part of the number.
Mod is for "Modular" arithmetic. It produces the "remainder" after dividing by a given number.
AND and OR are Boolean operators for Boolean algebra.
LSH is a "Left SHift" operator. This is a "bitwise" operator.