问题
选择题
如果等式1992+1994+1996+1998=5000-□成立,则□中应当填的数是( )
A.5
B.-980
C.-1990
D.-2980
答案
设□的数是x,
则1992+1994+1996+1998=5000-x,
即7980=5000-x
∴x=5000-7980=-2980.
故选D.
如果等式1992+1994+1996+1998=5000-□成立,则□中应当填的数是( )
A.5
B.-980
C.-1990
D.-2980
设□的数是x,
则1992+1994+1996+1998=5000-x,
即7980=5000-x
∴x=5000-7980=-2980.
故选D.