This paper looks in detail at the algorithms used by the Texas Instruments TI-83 calculator to calculate the square root of x, the solution to Ax = b and the trigonometric functions sine and cosine. What is exciting about these algorithms is that for various reasons, TI uses techniques that are not necessarily well-known or frequently used by today's numerical analysis community. I have written the explanations of these algorithms in such a way that high school math teachers as well as bright high school students searching for enrichment may use them.