(1)220/240/260/_/_
(2)750/700/650/_/_/_
(3)1000/_/_/_/100/1125/1150
(4)2001/2011/2021/_/_
add 20
subtract 50
try the others -- #3 has a typo
(2)750/700/650/_/_/_
(3)1000/_/_/_/100/1125/1150
(4)2001/2011/2021/_/_
subtract 50
try the others -- #3 has a typo