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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 6: Bài tập 1: Tính hợp lí nhất: a) (-25 + 97) – (-346 + 25 + 97) b) – (52 –16 – 34) + (52 — 34) c) –2003 + (-21+ 75 + 2003) – (-21 – 25 +

Toán Lớp 6: Bài tập 1: Tính hợp lí nhất:
a) (-25 + 97) – (-346 + 25 + 97)
b) – (52 –16 – 34) + (52 — 34)
c) –2003 + (-21+ 75 + 2003) – (-21 – 25 + 239)
d) (-49 + 57 – 32 + 45)– 73 +32 + 21- ( 57 + 21 -49 + 45)
e)-(-23 + 19 – 11 -29) + (-23 + 13 – 11) + 87 – 29
Làm các bước trung gian + hợp lí giúp em ạ giúp em với ạ em cho 5*

Comments ( 1 )

  1. a) ( – 25 + 97 ) – ( – 346 + 25 + 97 )
    = – 25 + 97 + 346 – 25 – 97
    = ( – 25 – 25 ) + ( 97 – 97 ) + 346
    = ( – 50 ) + 0 + 346
    = 296
    b) – ( 52 – 16 – 34 ) + ( 52 – 34 )
    = – 52 + 16 + 34 + 52 – 34
    = ( – 52 + 52 ) + ( 34 – 34 ) + 16
    = 0 + 0 + 16
    = 16
    c) – 2003 + ( – 21 + 75 + 2003 ) – ( – 21 – 25 + 239 )
    = – 2003 – 21 + 75 + 2003 + 21 + 25 – 239
    = ( – 2003 + 2003 ) – ( 21 – 21 ) + ( 75 + 25 ) – 239
    = 0 – 0 + 100 – 239
    = 100 – 239
    = – 139
    d) ( – 49 + 57 – 32 + 45 ) – 73 + 32 + 21 – ( 57 + 21 – 49 + 45 )
    =- 49 + 57 – 32 + 45 – 73 + 32 + 21 – 57 – 21 + 49 – 45
    = ( – 49 + 49 ) + ( 57 – 57 ) – ( 32 – 32 ) + ( 45 – 45 ) + ( 21 – 21 ) – 73
    = 0 + 0 + 0 + 0 + 0 – 73
    = 0 – 73
    = – 73
    e) – ( – 23 + 19 – 11 – 29 ) + ( – 23 + 13 – 11 ) + 87 – 29
    = 23 – 19 + 11 + 29 – 23 + 13 – 11 + 87 – 29
    =( 23 – 23 ) – 19 + ( 11 – 11 ) + ( 29 – 29 ) + 13 + 87
    = 0 – 19 + 0 – 0 + 13 + 87
    = – 19 + 13 + 87
    = – 19 + ( 13 + 87 )
    = – 19 + 100
    = 81

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222-9+11+12:2*14+14 = ? ( )

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