Uarco has 40 homework problems for his math class. He got \( 60 \% \) of them done during his study k. How many problems does Marco have left to do?

Uarco completed \( 60 \% \) of 40 homework problems, which is calculated as \( 0.60 \times 40 = 24 \) problems. To find out how many problems he has left, we subtract the number already completed from the total problems: \( 40 - 24 = 16 \). So, Uarco has 16 homework problems left to do. Speaking of math, did you know that percentages have been used since ancient times? The concept can be traced back to the Romans and their sophisticated economic systems, where selling and buying included calculations of taxes and profits, long before calculators existed. It's fascinating how a simple percentage can bridge centuries of arithmetic evolution! If you're tackling similar percentage problems, a common mistake is to miscalculate what the percentage means in a real-world context. Always double-check your figures by converting percentages into fractions or decimals to ensure accuracy! For example, remembering that \( 60\% \) is the same as \( \frac{60}{100} \) or \( 0.6 \) can go a long way in preventing errors.