Gurugram-based online doubt solving platform Doubtnut has raised over ₹23 crore in a funding round led by Sequoia India's startup accelerator and incubation programme Surge. WaterBridge Ventures and Omidyar Network India, among others, also participated. Founded by IIT Delhi alumni Tanushree Nagori and Aditya Shankar, the startup gives its users video solutions to math problems.