tinh hop li (279-1987)+(-18+1987-279) -(3251+415)-(2000+585-251) -25-26-27-28-29+15+16+17+18+19 71-(-30)-18+(-30)=118

0 bình luận về “tinh hop li (279-1987)+(-18+1987-279) -(3251+415)-(2000+585-251) -25-26-27-28-29+15+16+17+18+19 71-(-30)-18+(-30)=118”

1. a.(279-1987)+(-18+1987-279) = 279 – 1987 -18+1987 – 197 = (279-279)+91987-1987)-18=-18

   b.-(3251+415)-(2000+585-251) = -3251-415-2000-585+251 = (-3251 + 251) -(415+585)-2000 = -3000 – 1000 – 2000 =-6000

   c.-25-26-27-28-29+15+16+17+18+19 =  (-25+15)+(-26+16)+(-27+17)+(-28+18)+(-29+19) = -10-10-10-10-10=-50

   71-(-30)-18+(-30)+118 = 71 + 30 -18 – 30 = (30-30) + (118-18) + 71 = 100 + 71 = 171

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2. Đáp án:

   a.(279-1987)+(-18+1987-279) = 279 – 1987 -18+1987 – 197 = (279-279)+91987-1987)-18=-18

   b.-(3251+415)-(2000+585-251) = -3251-415-2000-585+251 = (-3251 + 251) -(415+585)-2000 = -3000 – 1000 – 2000 =-6000

   c.-25-26-27-28-29+15+16+17+18+19 =  (-25+15)+(-26+16)+(-27+17)+(-28+18)+(-29+19) = -10-10-10-10-10=-50

   71-(-30)-18+(-30)+118 = 71 + 30 -18 – 30 = (30-30) + (118-18) + 71 = 100 + 71 = 171

    

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