=π×
=(立方分米)
答:这个圆柱的体积是立方分米.
故选:A.
21.【解答】解:因为甲数是乙数的倍数,
所以甲和乙的最大公约数是乙;
故选:B.
22.【解答】解:某次月考,甲同学95分记作+5分,则标准成绩为:95﹣5=90分,
乙同学的成绩记作﹣3分,则乙同学的实际成绩是:90﹣3=87(分)
答:乙同学的实际成绩是87分;
故选:B.
23.【解答】解:312÷(312+288)
=312÷600
=52%
答:男生占全校人数的百分数为52%.
故选:B.
四、计算题.(28分)
24.【解答】解:
1﹣0.8=0.22.5×0.24=0.62÷=÷=
36×25%=93.26+3.5=6.76×=+=
25.【解答】解:(1)×350×
=200×
=75
(2)3.68÷[1÷(1﹣)]
=3.68÷[1÷0.1]
=3.68÷10
=0.368
(3)8.59×99
=8.59×(100﹣1)
=8.59×100﹣8.59×1
=859﹣8.59
=850.41
(4)2.25×48+775×0.48
=2.25×48+7.75×8
=(2.25+7.75)×8
=10×48
=480
26.【解答】解:(1)x﹣x=
x=
x÷=÷