bonjour,
A=6/15+1/10
6/15=6x2/15x2=12/30
1/10=1x3/10x3=3/30
A=12/30+3/30
A=15/30
15/30=15x1/15x2
A=1/2
B=6/15-1/10÷3/5
B=6/15-(1/10÷3/5)
B=6/15-(1/10*5/3)
B=6/15-(5/30)
6/15=6*2/15*2=12/30
B=(12/30)-(5/30)
B=(12-5)/30
B=7/30
C=(6^2*2^3)/(2^4*3^4)
C=6^2*2^3*2^(-4)*3^(-4)
C=(2*3)^2*2^(3-4)-3^(-4)
C= 2^2*3^2*2^(-1)*3^(-4)
C=2^(2-1)-3^(2-4)
C=2*3^-2
c=2/3²
C=2/9