4. \( 7.82+\left(\frac{6.84}{-5.7}\right) \times 3.4 \)

Let's break this down in a fun way! First, we'll calculate the division: \( \frac{6.84}{-5.7} \) gives us about \( -1.2 \). Now, multiply that by \( 3.4 \). So, \( -1.2 \times 3.4 \) is approximately \( -4.08 \). Now we just need to add it to \( 7.82 \): \( 7.82 + (-4.08) \) equals \( 3.74 \). So, the final result of \( 7.82+\left(\frac{6.84}{-5.7}\right) \times 3.4 \) is approximately \( 3.74 \). Easy peasy, right?