What is the modulo $5$ remainder of the sum $1+2+3+4+5+ \ldots + 120+121+122+123?$
Question:
What is the modulo $5$ remainder of the sum $1+2+3+4+5+ \ldots + 120+121+122+123?$
Answer:
Let's think step by step.

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What is the modulo $5$ remainder of the sum $1+2+3+4+5+ \ldots + 120+121+122+123?$
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