תּלמוד אויף במדבר 35:7

“Forty-eight cities” (Numbers 35:7). If, on the other hand, the scribe is uncertain as to his number, let him ask the Tanna how many he counts and deduct therefrom forty-eight and he will find his solution. As a mnemonic, take the phrase, “The Scribe is sparing, the Tanna is redundant.”