15^2-5x[5^56:5^30+5x5^21-5^26]÷25^10
15^2-5x[5^26+5^21-5^26]÷25^10
15^2-5x5^21:25^10
15^2-5x5^21:(5^2)^10
15^2-5x5^21:5^20
15^2-5x5^1
15^2-5
225-5=220
Eu zic ca e bn....
