Clear, step-by-step walk-throughs for calculating percentages, credit-weighted GPAs, standard deviation, and algebra.
A percentage is a proportion expressed as parts per hundred. To calculate a percentage of any number, convert the percentage to a decimal by dividing by 100 and multiply by the total amount. To find what percentage one number represents of another, divide the partial amount by the total amount and multiply the result by 100.
Grade Point Average (GPA) is calculated by converting each letter grade into a numerical point value (usually on a 4.0 scale), multiplying that value by the course's credit hours to determine 'quality points', summing the quality points for all classes, and dividing by the total number of credit hours attempted.
Standard deviation measures how spread out a set of numbers is from its average (mean). A small standard deviation means the values cluster tightly around the mean; a large standard deviation means the values are spread widely. It is calculated as the square root of the variance, which is the average of the squared differences between each value and the mean.
A scientific calculator extends basic arithmetic with functions for powers, roots, logarithms, trigonometry, and constants like π and e, and it always evaluates expressions using standard order of operations: parentheses first, then exponents, then multiplication/division, then addition/subtraction.