Where do the numbers in the explanation calculation's come from?

Fearned $110,000 of employment income in the current year. His employer with held CPP and El premiums of $3,754 as well as income tax. F's marital status is single. What is F's federal tax payable for the current year? 12,633 Explanation [($17,230 + ($110,000 - $97,069) x 26%) - ($13,229 - $1,245 +3,754) > 15%)]