Jony excels ________ mathematics.

• শূন্যস্থানে সঠিক উত্তর হবে - in.
- Complete sentence: Jony excels in mathematics.

• Excel in:
English Meaning - To be very good at doing something.
Bengali Meaning - দক্ষ।

• Excel (in/at something)-
- She excels in creative writing.
- Ratul excels in graphic design.

• Excel (at doing something)
- The team excels at turning defence into attack.

Source:
1. Accessible Dictionary by Bangla Academy.
2. Oxford Learner's Dictionary.