求未知数x.(1)x﹣25%x="1.8" (2)x:50=1.5:75 (3)x+6×4=46
计算: (1)73× (2) 166÷41
计算:(1)×37(2)2004×
计算:
计算:(1998+19981998+199819981998+…)÷(1999+19991999+199919991999…)×1999