math 1
math 2
math 3
math 4
math 5
100

1+1×6+9

16

100

42

16

100

982 - 982

0

100

987 - 76

911

100

5190

1

500

x2 = 81

9

2000

2x - 1 = 63

6

2000

log2(128) = 

7