Find the missing addend in XV + ______ = XLI

Here are the solutions to the mathematics problems:

1) B. Hundred thousand
The number is 2,858,247. The underlined digit is the second 8 from the left.
The place values are:
7 - Ones
4 - Tens
2 - Hundreds
8 - Thousands
5 - Ten thousands
8 - Hundred thousands
2 - Millions
The underlined digit 8 is in the hundred thousands place.

2) B. XXVI

Step 1: Convert the Roman numerals to standard numbers.
$XV = 10 + 5 = 15$
$XLI = 40 + 1 =