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Calculați folosind factorul comun:
a) 72×27-27×18+(39×93-39×39)÷54
b)4756+34-4756+4756×76


Răspuns :

a)
72×27-27×18+(39×93-39×39)÷54 =

= 27 ×( 72 - 18) + 39×(93 - 39) : 54 =

= 27 × 54 + 39 × 54 : 54

= 1 458 + 39 × 1 =

= 1458 + 39 =

= 1 497


b)
4756+34-4756+4756×76 =

= 4756×(1 - 1 + 76) + 34 =

= 4756 × 76 + 34 =

= 361 456 + 34 =

= 361 490