A:4
B:5
C:6
D:7
38 +0.625=____
1÷0.05=____
19 ×8.1=____
1÷ 37 =____
45 ÷ 58 =____
12 ﹣ 13 =____
0.1÷10%=____
a﹣ 25 a=____
解方程组:2x+y=4x-y=-1
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