better than expected

I did well in the exam.

私は試験がよくできました

I did better in the exam than expected.

私は予想より試験がよくできました

I did better in the exam than expected today.

私は予想より今日試験がよくできました

I did better in the exam than expected today at school.

私は予想より今日学校で試験がよくできました

I did better in the difficult mathematics exam than expected today at school.

私は予想より今日学校で難しい数学の試験がよくできました