1. Print Hello World using php <? php echo " hello world "; ?> 2. Addition of 5 numbers <? php $ a = 5 ; $ b = 6 ; $ c = 5 ; $ d = 2 ; $ e = 9 ; echo $ a + $ b + $ c + $ d + $ e ; ?> a. 3. Add, multi, sub, div all operators in one program <? php $ a = 5 ; $ b = 10 ; echo " addition is ", $ a + $ b ," < br > "; echo " multiplication is ", $ a * $ b ," < br > "; echo " division is ", $ a / $ b , " < br > "...