Which of the following numbers should replace the missing denominator in order to add the fractions? 25/82 + 13/?

Question

1. 82

2. 13

3. 25

4. 28

Answer 1

4. 28

Answer 2

25//82 +13/82 = 38 / 82 = 19/41

Answer 3

Ummmhhh, you need a "common" denominator, so 82
The bot misses another obvious one!

Answer 4

Just ignore the silly bot.