#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
