Blood Type Compatibility. Your ABO blood type is based on the presence or absence of the A and B antigens on your red blood cells. The A blood type has only the A antigen and the B blood type has only the B antigen. The AB blood type has both A and B antigens, and the O blood type has neither A nor B antigen.
Green Triangle. The green triangle appears in the upper left hand corner of a cell when there is an error in a formula. Sometimes Excel will report an error when you use text in a box and the program believes it is part of a formula. When you click on the green triangle there will be a yellow box that looks like a road sign with an exclamation point in it. This button is the Trace Error option that will help you correct your formula.
Steps. 1. Open Excel. Ad. 2. Notice there are rows and columns. 1  Each column has a capital letter on the top to show what column it is. 2  Each row has a number to the immediate left of the first column, to show what row it is. 3  For example, the address of the cell in the first column, first row is A1. Each column has a capital letter on the top to show what column it is. 2  Each row has a number to the immediate left of the first column, to show what row it is. 3  For example, the address of the cell in the first column, first row is A1. 4  The address of the cell in the second column, third row is B3.