Directed numbers

Adding and subtracting numbers.

But just imagine that Jonathon has $5 but owes $10 to Stephen. After Jonathon pays Stephen $5 he will still owe him another $5. We can write this mathematically. If Jonathon has $5 then we say he has +$5 but if he owes $5 we say he has -$5. So we will use the negative sign(-) to mean money owed or money given away.

Do the following exercises.
Write a methematical expression for the following situations.

Situation	Money	Mathematical expression
Jonathon owes $10 to Stephen. Jonathon's dad gives him $20. If Jonathon pays Stephen how much money does he have.	-$10 -$20 +$20 +$10	-10 + 20 = 10 10 - 20 = -10 -20 + 10 = -10
Stephen has $30 but he spends $2 on a toy and gives $10 to his brother.	-$10 +$18 +$20	-10 + 20 = +10 +0 - 20 = -10 -30 + 12 + 2 = -18 +30 - 2 - 10 = +18
Peter has no money but owes Stephen $30 and Jonathon $29.	-$59 +$59 +$29 -$29	+30 + 29 = +59 -30 - 29 = -59 -30 + 29 = +1
Peter owes Stephen $20 and Jonathon $5. He earns $30 and spends $3 on an icecream. How much money does Peter have?	-$2 +$30 $2 -$20	+30 + 29 = +59 -30 - 20 -5 + 3= -52 -20 - 5 + 30 - 3 = +2