AMC 8 1987 Problem 21

Suppose $n^{*}$ means $\frac{1}{n}$, the reciprocal of $n$. For example, $5^{*}=\frac{1}{5}$. How many of the following statements are true?

i) $3^*+6^*=9^*$ ii) $6^*-4^*=2^*$ iii) $2^*\cdot 6^*=12^*$ iv) $10^*\div 2^* =5^*$

$\text{(A)}\ 0 \text{(B)}\ 1 \text{(C)}\ 2 \text{(D)}\ 3 \text{(E)}\ 4$