Given;
The given exression is 455+229.
The objective is to use compatible numbers to estimate the addition.
Step-by-step explanation:
Consider the number is 455. Since the last digit is 5, the compatible number by rounding off is 450.
Similalrly, consider the number 229. Since the last digit is 9 which is greater than 5, the compatible number by rounding off is 230.
Addition of compatible numbers:
Then, the estimated value will be,
Hence, the estimated value is 680.