Christopher tried this number trick -write down ur street number -multiply by 2 -add number of days in a week -multiply by 50 -add the last two digits of ur phone number -subtract number of days in a year -add 15 determine which line the error occurs n represent any street number 1) 2n multiply by 2 2) 2n+7 days in a week 3) 100n+7 multiply by 50 p represent last two numbers of phone number 4) 100n+7+p add phone digits 5) 100n+p-358 subtract days in a year 6) 100n+p-343 add 15