Question:
Let ${ }^{* \prime}$ be the binary operation on the set $\{1,2,3,4,5\}$ defined by $a^{* \prime} b=$ H.C.F. of $a$ and $b$. Is the operation $^{* \prime}$ same as the operation * defined in Exercise 4 above? Justify your answer.
Solution:
The binary operation *' on the set $\{1,2,34,5\}$ is defined as $a^{* \prime} b=$ H.C.F of $a$ and $b$.
The operation table for the operation ${ }^{* \prime}$ can be given as:
We observe that the operation tables for the operations ${ }^{*}$ and ${ }^{* \prime}$ are the same.
Thus, the operation *' is same as the operation*