bonjour déjà

ex 7

1 / (9x9) = 1 / 9² = 9⁻²

1 / (7x7x7) = 1 / 7³ = 7⁻³

etc

ex 9

10⁻¹ = 1/10¹ = 1/10 = 0,1

10⁻² = 1/10² = 1/100 = 0,01

10⁻³ tu as compris

2⁻¹ = 1/2¹ = 1/2 = 0,5

etc