Move the C scale by sliding the center sliding portion so that the C value is zero at the number of the D scale you wish to multiply by. At the number you want to multiply on the D scale, the C scale should read 0.
Slide the cursor over the other number you are multiplying by on the C scale. The line should be on this number on the C scale and should extend down to the D scale.
Read the number the cursor is over on the D scale. This is your result.
Slide your cursor to the number you would like to divide on the D scale.
Leave the cursor in this place, and move the C scale so that it lines up with the cursor at the number you would like to divide by.
Slide the cursor to the closest 1 on the C scale. This will be at the far right or left of the C scale.
Read the number on the D scale. This is your result.
Move all the scales so that they line up.
Slide the cursor over the number you would like to square on the C scale.
Read the number on the B scale, indicated by the cursor.
Move the decimal point based on approximation. For instance, 3 squared is 9, but the reading on the B scale will be 0.9. It is impossible for the square of 3 to be less than 3, so the decimal is moved to the right one place to give a result of 9.
Figure out which of the two B scales to use. The left one is used for numbers with an odd number of digits like 5 and 500. The right one is used for numbers with an even number of digits like 50.
Move the decimal of the number you would like to get the square root of to the left to make the number between 1 and 10. If you wanted to find the square root of 42, you would move the decimal one place to the left to give you 4.2. You also need to drop all zeros at the end of the number. For instance, if your number is 88,000, you drop the zeros to get 88 and move the decimal left one to the left to get 8.8.
Slide the scales so that they all line up.
Slide the cursor over to the number on the correct side of the B scale.
Read the number on the C scale under the cursor. Adjust the decimal point as you did when squaring a number. This is your result.