Desmos - A beautiful, innovative, and modern online graphing calculator.
RANDOM.ORG - RANDOM.ORG offers true random numbers to anyone on the Internet.
WolframAlpha - WolframAlpha brings expert-level knowledge and capabilities to the broadest possible range of people—spanning all professions and education levels.
Random Number Generator - Randomly generate integers or floating point numbers within a given range and specified discrete or continuous statistical probability distribution.
GeoGebra - GeoGebra is free and multi-platform dynamic mathematics software for learning and teaching.
Randommer - Generate random number, telephone numbers, text, hashed and social security numbers