口算下列各题。.t.[(X
540+370=/I*c(n(N1j4@.t.[(X
450+560=3U-j-V2P){5b3f6S3v,M1H.t.[(X
750-180= 1h6E9]1C7L*b.t.[(X
320-190=:E0|7o+k:H+r.t.[(X
490+250=4L2@+B6A.a-`3A'[8E)R.G6J/v,l*n.t.[(X
170+290=,h+[,o:p.t.[(X
620-240=3a5K3?+^1^3W+e,v;u8?.t.[(X
850-590=+j,X'l/g3S-K5q*Z*P3b;n2@6W,g:h0R3y/h1[.t.[(X