The expression "5 × 4" represents a multiplication problem where the number 5 is multiplied by the number 4. In simple terms, this means you have five groups of four items each. When you calculate "5 × 4," the result is 20. This means that if you have five sets of four, you will have a total of twenty items. Multiplication is a quick way to add the same number multiple times, so instead of adding 4 five times (4 + 4 + 4 + 4 + 4), you can simply multiply to get the same answer.