how to sort floor level problem

[gasmarc]

I have a painted concrete floor that goes into the front room where there are marley tiles but am missing a few where the threshold is. Whats the best solution a mortar mix feathered in going to work , Thanks

 

[bobasd]

traffic goin over a feathered mortar mix will break it up in no time.
post a photo.

 

[dazlight]

Best use a latex screed like
Ardex NA
Stopgap 1200 Pro
Uzin Gold