Question

用简便方法计算,3x3/5x25x2/5+37.9x6x2/5

Answer 1

用简便方法计算,
3x3/5x25x2/5+37.9x6x2/5
=3/5x25x6/5+37.9x2x6/5
=15x2/5+75.8x2/5
=(15+75.8)x2/5
=(90+0.8)x2/5
=90x2/5+0.8x2/5
=36+8/25
=36又8/25