55+4 = 67+2 = 40+50 = 80 – 30 = 70 – 20 =
55+40 = 37+60= 40+28 = 76 +10 = 40+8=
83 – 20 = 74 – 60 = 37 – 3 = 63 – 20 = 46 – 10 =
42+545+2 34 – 434+4 63+678 – 6
48+11 23+63 83 – 50 79 – 52 48 – 11 99 – 88
>>>>>
还要写多少个字?