Can you guys give me the working out and the answers?​

#1 (15)

50%= 1/2

1/2 of 30 is the same as 30÷2=15

#2 (20kg)

25%= 1/4

1/4 of 80 is the same as 80÷4= 20

#3 (30cm)

1/3 of 90 is the same as 90÷3=30

#4 (8m)

2/3 of 12 is the same as 12÷3= x2

12÷3= 4(2)= 8

#5 (70)

10% = 1/10

1/10 of 700 is the same as 700÷10= 70

#6 (280)

40%= 4/10

700÷10=x(4)

70(4)=280

#7 (2700 m)

9/10

3000÷10=x(9)

300(9)= 2700