What is the additive and multiplicative inverse of 0.25

The additive inverse is -0.25. 
The multiplicative inverse is 1/0.25, or 1/(1/4), or 4. 

Addative inverse makes it 0
0.25+AI=0
minus 0.25
AI=-0.25
the addative inverse is -0.25

multiplicatiive inverse is what times that number=1
0.25 times MI=1
divide both sides by 0.25
MI=1/0.25
MI=4

addative inverse is -0.25
multiplicative inverse is 4