长方体四组长宽高,除以4=1长+1宽+1高.52/4=13(cm)
1长+1宽+1高减1长-1宽=1高.13-6-4=3(CM) 选B
甲工效1/12 乙工效1/15 一件工作为单位"1".
1/12+1/15=9/60
1除以9/60
=1*60/9
=60/9
=3/20
长方体四组长宽高,除以4=1长+1宽+1高.52/4=13(cm)
1长+1宽+1高减1长-1宽=1高.13-6-4=3(CM) 选B
甲工效1/12 乙工效1/15 一件工作为单位"1".
1/12+1/15=9/60
1除以9/60
=1*60/9
=60/9
=3/20