I think my synapses are not firing this morning(PST). I am reviewing fixed income and attempting to calculate the price of a treasury bill on a discount basis. On CFAI Book 5 Page 439 they have the following: 1 - 5.18% (155/360) = 0.97769722 I get 0.408252778 Also: 1 - 5.23% (351/360) = 0.9490075 I get 0.9240075 Am I just being a retard here?

I got their answer for the first and second. Inputting into the calc wrong?

I think you are I’m afraid. I get 0.97769722. Try this ((155/360) x 0.0518 x -1) + 1 and you will get the correct answer

It was my input into the calculator. Time for another cup of coffee.

1 - (.0518*155/360) = .9776972222 1 - (.0523 * 351/360) = .9490075 which are the book answers. Key is to use the ( operator ) appropriately. That is the way I do left->right operations on the calc. Otherwise do the inside first as newsuper has done