Answer:
29
Step-by-step explanation:
According to the associative property of addition, for any given real numbers, a,b, and c;
[tex]a+(b+c)=(a+b)+c[/tex]
[tex]1+10+18=(1+10)+18[/tex]
[tex]1+10+18=11+18[/tex]
[tex]1+10+18=29[/tex]
Or;
[tex]1+10+18=1+(10+18)[/tex]
[tex]1+10+18=1+28[/tex]
[tex]1+10+18=29[/tex]
