1. State the problem: Compute $91387 + 2998,74$. 2. Formula and rules: Addition is commutative and associative, so $a+b=b+a$ and when adding decimals you must align decimal places by place value. 3. Convert decimal separator: The number $2998,74$ uses a comma as the decimal separator, so convert it to a point: $2998,74 = 2998.74$. 4. Align decimals: Write $91387$ as $91387.00$ so both numbers have two decimal places. 5. Add integer and decimal parts separately: $91387 + 2998 = 94385$ and $0.00 + 0.74 = 0.74$. 6. Combine results to get the final sum: $$94385 + 0.74 = 94385.74$$ 7. Final answer: $94385.74$.