4.5*10^3/9*10^7=4.5/9*10^3*10^7=0.5*10^3*10^7. a^b*a^c=a^(b+c), so 10^3*10^7=10^(3+7)=10^10. 0.5*10^10=5*10^9, since we want to write in scientific notation where the leading number is bigger than one and smaller than 10.
3/4 - per skirt >> 0.75
5 5/14 - unused >> 5.36 (approximately)
5.36/0.75= 7.14666...
Regina can make 7 skirts
