if { x } is the product of all even integers from 1 to x inclusive , what is the greatest prime factor of { 22 } + { 20 } ?
"soln : { 22 } + { 20 } = 22 * { 20 } + { 20 } = 23 * { 20 } answer : a"
add(divide(add(22, 20), const_2), multiply(1, const_2))