Adding 2-Digit Numbers by Making 10s

In this video, students learn how to add up to four 2-digit numbers using the strategy of making 10s. Add numbers in different orders and understand that the sum remains the same. The lesson also highlights the concept of friendly numbers, which are multiples of 10 that make addition easier. Students practice this strategy by calculating the total cost of various items, such as lunch, movie snacks, and bowling expenses.