a+20{#blank#}1{#/blank#}20+a                   496-120-230{#blank#}2{#/blank#}496-(120+230)

280-70+30{#blank#}3{#/blank#}280-(70+30)      12+(8+13){#blank#}4{#/blank#}(12+8)+13

234+45×32{#blank#}5{#/blank#}32×45+234      192+(95—75){#blank#}6{#/blank#}192+95+75

①25×125×4×8

②37×28+37×2

③(20+8)×125

④173+428+27

⑤38×101

⑥44×25

①86+49+351

②132-68-32

③143+64+57+136

④12×24-12×14

⑤72×125

⑥4600÷25÷4

⑦76×237+237×24

⑧99×38+38

⑨104×25

⑩43×98

41＋154＋259={#blank#}1{#/blank#}