Posted by kamleen on .
14. (32+48)+52=32+(48+52) associative
15. 256+0=256 identity property
16.3/10x10/3=1 inverse property
17.1x143=143 identity property
18. 81+(81)=0 inverse property

math 
PsyDAG,
18. Is 81 the inverse of 81?
The others look right.