very easy
1% of 100
1
15% of 100
15
10% of 80
8
1% of 130
1.3
3% of 600
18
2% of 100
2
20% of 100
20
10% of 40
4
7% of 1100
77
50% of 110
55
3% of 100
3
35% of 100
35
30% of 80
24
3% of 250
7.5
6% of 500
30
4% of 100
4
45% of 100
45
6% of 400
48
20% of 130
26
4% of 3000
120
5% of 100
5
60% of 100
60
1% of 900
9
85% of 994
844.9
4% of 2000
80