Select the missing number from the given series: 98, 70, 42, 14, ?, -42

Each term decreases by a constant 28: 98 minus 28 is 70, 70 minus 28 is 42, 42 minus 28 is 14. So the next term is 14 minus 28, which is -14, and -14 minus 28 gives -42, matching the last term.