What is the error in this calculation? To add $\frac{3}{8} + \frac{1}{2}$, a student writes $8 \cdot \frac{3}{8} + 8 \cdot \frac{1}{2} = 3 + 4 = 7$.

Multiplying by the LCD is a method for solving equations, not simplifying expressions.

The LCD of 8 and 2 is 16, not 8.

The distributive property was applied incorrectly.

The final addition is wrong; $3 + 4$ is not 7.

Solving Linear Equations II Practice — Grade 4 amc_math