Every expanding question is the same two strokes: outside × first term, then outside × second term. Write both results out, keeping their signs, and you're done.
The Two Strokes
One — multiply the outside number by the first term inside. If it's 3(x + 4), that's 3 × x = 3x.
Two — multiply the outside number by the second term. 3 × 4 = 12. Then just write them together: 3(x + 4) = 3x + 12. Done.
A Worked One
Expand 5(2a + 3). First stroke: 5 × 2a = 10a. Second stroke: 5 × 3 = 15. Put them together: 5(2a + 3) = 10a + 15. Notice 5 × 2a means multiply the number part (5 × 2 = 10) and carry the a along.
Negatives Are No Different
If a term inside is being subtracted, treat it as a negative and multiply normally. 6(n − 5) = 6n − 30. A negative inside times a positive outside stays negative — same multiplication rules you already know, no special case to memorise. Run the toy until expanding feels as automatic as your times tables.