Question

Calculați rapid folosind formulele de calcul prescurtat
a)98^2-2^2
b)994^2-6^2
c)93•107
d)192•208

Answer 1

a²-b²=(a-b)(a+b)
98²-2²=(98-2)(98+2)=96x100=9 600
994²-6²=(994-6)(994+6)=988x1000=988 000
93x107=(100-7)x(100+7)=100²-7²=10 000-49= 9 951
192x208=(200-8)x(200+8)=200²-8²=40 000-64=39 936