Bài 2 : Tính bằng cách thuận tiện nhất
a) 1987 + 1992 + 1997 + 2002 + 2007 = ................................
= ................................
= ................................
b) 4,25 + 4,32 + 4,39 + 4,46 + 4,53 =.................................
=................................
=..............................
c) 3/5 + 3/4 + 2/5 + 5/8 + 1/2 =.........................
=........................
=........................
d) 27/8 - 7/3 + 4/3 - 2 =.........................
=........................
=........................
\(a,1987+1992+1997+2002+2007\)
\(=\left(2007+1987\right)x5:2\)
\(=9985\)
\(b,4.25+4.32+4,39+4,46+4,53\)
\(=\left(4,53+4,25\right)x5:2\)
\(=21.95\)