数的世界(2)1.a+b b+aax(bxc) (axb)xcaxc+bxc (a+b)xc2.41+216+159=(41+159)+216 =200+216 =416 45x16=45x2x8=90x8=72012x13x5=12x5x13=60x13=780230-76-124=230-(76+124) =230-200=3019+99x19=19x(1+99)=19x100=1900256x9-56x9=(256-56)x9=200x9=18003.116 18900 694.(1)0 1231 123412 12345(2)(3333333-21)÷27=123456 (33333333-24)÷27=123456705WaNg.CoM5.420÷(5x6)=420÷30 |