2+3+4= 7-7+5= 8+2-10= 9+2-3=
4+( )=9 ( )+7=10 16-( )=10 ( )+( )=13
4+3= 10-6= 8+9= 16-3= 12+7=
15-2= 4+7= 10-4= 10-9= 11+8=
14+5= 5+8= 17-4= 6+9= 15+3=
9+7-3= 6+4+8= 13-3+9= 7+7-4=
①(2.3+2.3+2.3+2.3)×2.5
②7.2×85%+2.8×0.85
③( + - )×24
④ ÷[ ×( - )]
⑤[( -0.25)× +0.3]÷