3154-129-465-406
= 3154-(129+465+406)
=3154-1000
=2154
219+648+51-138-548-62
=219+（648-548)+51-(138+62)
=219+100+51-200
=170
100+99-98-97+96+95-94-93+… +8+7-6-5+4+3-2-1
=100+99-98-97+96+95-94-93+… +8+7-6-5+4+3-2-1
=(100-98)+(99-97)+(96-94)+(95-93)+… +(8-6)+(7-5)+(4-2)+(3-1)
=2+2+2+… +2+2
=2*50
=100
2005+2004-2003-2002+2001+2000-1999-1998+…+5+4-3-2+1
=2005+(2004-2003-2002+2001)+(2000-1999-1998+1997)+…+(4-3-2+1)
=2005+0+0+…+0
=2005
=97+(1+2-3-4)+(5+6-7-8+9)+…+(93+94-95-96)
=97-4-4-…-4 共96/4=24个4
=97-4*24
=97-96
=1
或1+2-3-4+5+6-7-8+9+…+94-95-96+97
=1+(2-3-4+5)+(6-7-8+9)+…+(94-95-96+97 )
1+0+0+…+0
=1
612X366÷183
=612X(366÷183 )
=612X2
=1224
103X96÷16
=103X(96÷16 )
=103X6
=618
624X48÷312÷8
=(624÷312)X(48÷8)
=2X6
=12
238X36÷119X5
=238÷119X5 X36
=2X5 X36
=360