40°30′+30°40′=?90°-30°35′ - 知识问答

40°30′+30°40′=?90°-30°35′42″=?方法第一,

1个回答

40°30′+30°40′
=40°+30°+30′+40′
=70°+70′
=71°10′
90°-30°35′42″
=89°59'60"-30°35′42″
=59°+24'+18"
=59°24'18"

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