Duo needs to give a slow play option for words like these, or have lessons specifically on alternate pronunciations. I can't tell for certain how 十三 is supposed to be pronounced here. Same with some of the other numbers.
I thought this too, but as you drill more phrases your brain picks it up super fast. Reviewing earlier content it feels almost impossible not to recognize most words and phrases. I used to pull my hair out trying to understand "good night" and "thank you for the meal" lol