ex.10,dau coroana
[tex]( {5}^{2} - {4}^{2} ) \div 9[/tex]

Răspuns:
a) (5²-4²):9=(25-16):9=9:9=1
b) 12×35-12×24+12=420-288+12=144
c) [9²-2⁴×5⁹:(5⁴)²]:2²=(81-2⁴×5):2²=(81-16×5):2²=(81-80):2²=1:2²=1/2²=1/4=0,25