Worthless
The Tagalog word for invaluable is "di-matutumbas" or "hindi mapapantayan".
The stress in the word "invaluable" is on the second syllable - "val."
Instead of using the word challenging you can use the word gifted, special, special gifted.
invaluable man
there a 4
or
Will, when, why, it, can
Because of his wide experience, my father's advice usually proves to be invaluable.
I have a stomach ache.
Myself
mixture
are