Surplus is a noun and an adjective, not a verb. Therefore it does not have tenses.
The correct spelling for the past tense of "surplus" is "surplused."
I have seen surplused or surplussed. Not sure they are both right or not.
The past tense of "have" is "had."
The past tense of 'spell' is 'spelled'. 'Spelt' is also used in British English.
The past tense of "settle" is spelled as "settled".
The past tense of "murmur" is "murmured."
The past tense of discuss is discussed.
have in past tense is had
The past tense of "have" is "had."
The past tense of have is had.
The past tense of 'spell' is 'spelled'. 'Spelt' is also used in British English.
The past tense of "settle" is spelled as "settled".
The past tense is benefited.
The past tense is traveled.
The past tense is coasted.
The past tense is paddled.
The past tense is fared.
The past tense of discuss is discussed.
The past tense is roped.