46. Calculate: $79 \cdot 81+1$.
46. $79 \cdot 81+1=(80-1)(80+1)+1=80^{2}-1+1=6400$.

46. $79 \cdot 81+1=(80-1)(80+1)+1=80^{2}-1+1=6400$. 

(Note: The original text and the translation are identical as the content is a mathematical expression which is universal and does not change in translation.)