Using only addition and subtraction operations, what will replace the question mark (?) to logically complete the series below? 13, 10, 23, 20, 33, ?

Which movement aimed to promote Khadi, a hand-spun and handwoven cloth native to India?

Who were prominent leaders associated with the initial phase of the Telangana Rebellion (1946-1951) against the Nizam's rule and feudal landlords?

What was the immediate trigger for the Revolt of 1857?