# Backpropagation. Follow the numbers.

Backpropagation: Follow the Numbers is part of the 21IFM premium collection. The full lesson is currently locked.

The lesson brings together seven guided stages, real numerical forward and backward calculations, an interactive network, and thinking questions with hints.

Contact contactus@21ifm.com to ask about premium access. You can try our free Curves + Wiggles mini lesson to explore the teaching approach.

Canonical page: https://21ifm.com/ai/backpropagation

## Explore

- [Contact for premium access](mailto:contactus@21ifm.com?subject=Premium%20access%20%E2%80%94%20Backpropagation)
- [Try a free mini lesson: Curves + Wiggles](https://21ifm.com/quant/curvature-lift)
- [Explore Illustrated Mathematics](https://21ifm.com/)