/home/sites/rulefo/public/documents/main/5klass/matematika/5-1-13-1m.htm 5-1-13-1matem.
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, a b x,   x + b = a .
         a - b = x                a -
                                        b -
                                        x -
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, , -  
a - (b + c) = (a - b) - c         a - (b + c) = (a - c) - b

: 883 - (283 + 450) = (883 - 283) - 450 = 150
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 (a + b) - c = (a - c) + b, a > c  a = c (a + b) - c = (b - c) + a, b > c   b = c

: (447 + 568) - 147 = ( 447 - 147) + 568 = 868
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1. , :

48 (345+18)                   785 (285 + 34899)                 (573 + 233) - 273
643 - ( 70 + 343)              484 - 45 - 84                                885 - (185 + 450)
(370 + 89) - 170               (457 + 264) - 457                        6 780 - 128