Translate the words into equations: 'a number' becomes x, 'exceeds' means subtraction, 'times' means multiplication.
1Useful identities
Larger = (sum + difference)/2, smaller = (sum − difference)/2
(a + b)² = a² + b² + 2ab; (a − b)² = a² + b² − 2ab; a² − b² = (a + b)(a − b)
A two-digit number with digits x, y is 10x + y; reversing changes it by 9(x − y)