在算式7×9+12÷3-2中加一对括号后,算式的最大值是(  )A.75B.147C.89D.9

2025-01-18 16:53:53
推荐回答(1个)
回答1:

①7×(9+12)÷3-2
=7×21÷3-2,
=49-2,
=47;
②7×9+12÷(3-2)
=7×9+12÷1,
=63+12,
=75;
③(7×9+12)÷3-2C
=75÷3-2,
=25-2,
=23;
④7×(9+12÷3)-2
=7×13-2,
=91-2,
=89.
23<47<75<89,89最大.
故答案选:C.