Archimedes - Archimedes is a LaTeX and Markdown editor designed to make mathematical writing easy.
Potfolio - Platform to learn to invest by investing
Forex Hero - The currency trading game that teaches you forex and stock trading.
Ark7 - Choose a property and invest in shares
Overleaf - The online platform for scientific writing. Overleaf is free: start writing now with one click. No sign-up required. Great on your iPad.
INDX - INDX is a focused place for self-directed learning.