Question

Find $\text{'}a\text{'}$ so that the statement becomes true :

$(4+11)+17=(4+a)+11$

Answer 1

Addition is associative: This property says that changing the grouping of the addends does not change the sum.

i.e. $a+(b+c)=(a+b)+c$

$$\begin{gathered} (4+11)+17=(4+a)+11 \\ a=17 \end{gathered}$$

Therefore, the value of $a$ is $17$.