算一算。4j3^+x5V7I8I'u6L9O/R
1200-300=5g4f2d0a7C.A,T:X.] 3500+1000=*I3M2a)c:|4j3^+x5V7I8I'u6L9O/R
4000+5000=:m7y+\4|8j(P 400+700=7R'm-H-[/c4j3^+x5V7I8I'u6L9O/R
1000-600=6{6S1G:z5C1Z 2400-400=+e/`;Y/M4|8|-|4j3^+x5V7I8I'u6L9O/R
1500-900=9P:w4X-q1A'Y6[3n 200+800=:l*U-u/E;M4j3^+x5V7I8I'u6L9O/R
1400-600=;n7C6[3e+?0](N5Q1N/H/?.T 7000-6000=+a2D3p-L)W9\4j3^+x5V7I8I'u6L9O/R
170-90=3U2v4S:b6_-N5w 3000+7000=6`5d*?*}.p;h.e;i)f2c8S2k(w'P:h0X4j3^+x5V7I8I'u6L9O/R