Answer: 800,000Step-by-step explanation:Step 1: Identify the largest place value that is common or suitable for all numbers (so that rounding makes sense for each number). Since they can both be rounded to the hundred thousands, it’ll be easier.Remember: To round a number, you first look at the digit in the place value you want to round to. Then, check the digit immediately to its right. If that digit is five or higher, you increase the rounding digit by one. If it is four or lower, you leave the rounding digit as it is. After that, all the digits to the right are changed to zero. 423,462 -> 400,000416,418 -> 400,000Step 2: Find the sum of both numbers400,000 + 400,000 = 800,000