$$10\div 2$$ - 

The multiplier for a constant multiplicative rule

$$10\times 5$$ - 

The next value in a constant multiplicative sequence

$$10 - 2$$ - 

The value being added in a constant additive sequence

$$10 + 8$$ - 

The next value in a constant additive sequence

$$2\div 5$$ - 

The previous value in a constant multiplicative sequence

$$2 - 8$$ - 

The previous value in a constant additive sequence

$$(-12) + (-6) $$ - 

-18

$$(-12)\div (-6)$$ - 

2

$$(-12)-(-6)$$ - 

-6

$$(-12)\times (-6)$$ - 

72

$$12\times (-6)$$ - 

-72

$$12\div (-6)$$ - 

-2

$$1\over 2$$ - 

$${4\over 5}-{3\over 10} $$

$$11\over 10$$ - 

$${4\over 5}+{3\over 10} $$

$$8\over 3$$ - 

$${4\over 5}\div{3\over 10} $$

$$6\over 25$$ - 

$${4\over 5}\times{3\over 10}$$

$$25\over 6$$ - 

$$5\times{5\over 6}$$

$$6$$ - 

$$5\div{5\over 6}$$

..., 25, 35, ... - 

add 10

..., 45, 135, ... - 

multiply by 3

..., 45, 95, ... - 

add 10, add 30, add 50, add 70....

..., 35, 75, ... - 

double the previous value then add 5

..., 35, 65, ... - 

add 10, add 20, add 30, add 40 ...

..., 55, 215, ... - 

multiply by 4 then subtract 5