The_three_Rs
The three Rs
3 basic skills taught in schools: reading, writing, arithmetic
The three Rs[1] are three basic skills taught in schools: reading, writing and arithmetic (the "R's" refer to, "Reading, wRiting, and aRithmetic").[2] The phrase appears to have been coined at the beginning of the 19th century.
The term has also been used to name other triples (see Other uses).