四年级口算1000题(21)

55 -45 -200 56 -36 -184 = 57 -27 -168 = 58 -18 -152 = 59 -9 -136 60 + 0 -120 61 + 9 -104 62 + 18 -88 63 + 27 -72 = 64 + 36 -56 65 + 45 -40 = 66 + 54 -24 = 67 + 63 -8 = 68 + 72 + 8 = 69 + 81 + 24 70 -60 -260 71 -51 -244 = 72 -42 -228 = 73 -33 -212 = 74 -24 -196 = 300*400= 120*500=