1) Multiply the number of your brothers, "x" by 2. 
2x

2) Add 3. 
2x+3

3) Multiply by 5. 
(2x+3)(5)

4) Add the number of your sisters, "y". 
(2x+3)(5)+y

5) Multiply by 10. 
[(2x+3)(5)+y](10)

6) Add the number of your living grandparents, "z". 
[(2x+3)(5)+y](10)+z

7) Subtract 150. 
[(2x+3)(5)+y](10)+z150

NOW
SIMPLIFY STEP 7


Work
inside the brackets first, we need to multiply by 5.

[10x+15+y](10)+z150

Now
multiply by 10.

100x+150+10y+z150

Subtract
150 from the 150.

100x+10y+z

The number of brothers, "x", is in the 100's place, the number of sisters, "y", is in the 10's place, and the number living grandparents, "z" is in the 1's place. 