Dollars and Bills
I am learning to add integers (positive and negative numbers).
e.g. +5
e.g. -5
SAMPLE PROBLEM
Susan finds $7 in her piggy bank.
Unfortunately she owes her sister $5.
Recorded as -5
Recorded as +7
+7 + …… = …..
……… + …… = …..
+7 + -5 = …..
SAMPLE PROBLEM
=7 + -5 = …...
These are the coins that Susan has
($7).
This is the amount of money she
owes her sister ($5).
SAMPLE PROBLEM
=7 + -5 = …...
Step 1: She must use some of the
money to pay back her sister.
+5+-5=0
The amount of money
she now owes her sister.
That means she is left with $2
So…
+7 + -5 = 2
Now let’s try one together
+8 + -3 = ….
Step 1: We need to split the 8 so that some of it can be
used to pay back the $3 we owe. On a piece of paper split
the $8 into $3 (to pay back the debt) and the amount you
will have left over. Do this now.
Now let’s try one together
+8 + -3 = ….
Step 2: Now use the $3 to pay back the debt. Write the
equation that shows this on your paper now.
Now let’s try one together
+8 + -3 = ….
Step 3: We now know what’s left so it’s time to answer our
question. On paper write your answer to +8 + -3 = ?
Now try these questions on your own.
1) 6 + -3 = ….
6) 14 + -8 = ….
2) 9 + -4 = ….
7) 12 + -5 = ….
3) 12 + -8 = ….
8) 19 + -12 = ….
4) 13 + -7 = ….
9) 15 + -6 = ….
5) 17 + -4 = ….
10) 18 + -2 = ….
Only click again if you have completed all the questions
on the previous slide and you are ready to see the
answers.
1) 3
6) 6
2) 5
7) 7
3) 4
8) 7
4) 6
9) 9
5) 13
10) 16
Need some more practise? Try Pg65 of Teacher Tools Addition and
Subtraction Book Numeracy resources