efecteaza prin procedeul preferat 27×3 29×3 26×3 19×4

Răspuns :

81+87+78+76=168+134=302
27×3=9x3x3=9x9=81
 
29×3=(20+9)x3=20x3+9x3=60+27=87
sau
29×3=(30-1)x3=30x3-1x3=90-3=87

26×3=(20+6)x3=20x3+6x3=60+18=78

19×4=(20-1)x4=20x4-1x4=80-4=76