355,1:0,67+0,83•15=

Let's break down the expression step by step:

The expression given is:

\[ 355,1 : 0,67 + 0,83 \cdot 15 \]

1. Divide \( 355,1 \) by \( 0,67 \): \[ 355,1 \div 0,67 \approx 530,22 \]

2. Multiply \( 0,83 \) by \( 15 \): \[ 0,83 \cdot 15 = 12,45 \]

3. Now, add the results from steps 1 and 2: \[ 530,22 + 12,45 = 542,67 \]

So, the final result is approximately:

542,67