Questions: (15+) + 29 = 15 + (8 + 29)

Solve the equation $\left(15+\_\right)+29=15+(8+29)$ to find the missing value.

Simplify the right-hand side of the equation.

Calculate $8 + 29$: $8 + 29 = 37$. Now, the equation becomes $\left(15+\_\right)+29=15+37$.

Simplify further.

Calculate $15 + 37$: $15 + 37 = 52$. Now, the equation becomes $\left(15+\_\right)+29=52$.

Isolate the missing value.

Subtract $29$ from both sides of the equation: $\left(15+\_\right) = 52 - 29$. This simplifies to $\left(15+\_\right) = 23$.

Solve for the missing value.

Subtract $15$ from both sides: $\_ = 23 - 15$. This gives $\_ = 8$.

The missing value is $\boxed{8}$.

The missing value is $\boxed{8}$.