Transcript Document

LO Adding and subtracting with RAG
negative numbers
Key Words: Positive, Minus
17-Jul-15
Look at the set of questions on the starter activity sheet.
Attempt to answer all of them.
Don’t worry if you’re not sure if your answers are
correct. You will get the opportunity to change your
answers at the end of the lesson.
You can use the number line to help you.
Starter Activity
(+8) – (+3)=
(–8) + (–3)=
(–3) + (+8)=
(+3) – (+8)=
(+8) – (–3)=
(–8) – (–3)=
Starter Activity
(+8) – (+3)=
(–8) + (–3)=
(–3) + (+8)=
(+3) – (+8)=
(+8) – (–3)=
(–8) – (–3)=
Keep a record of your answers, you may want to
change them at the end of the lesson.
Mini whiteboards ready – one between two, you
must agree you answer with your partner.
Why is this ‘4’?
4
How much is this?
Making 3
Show me another way of making
3.
Can you do one using 11 charges
altogether?
How much is this?
How much is this?
–2
How much is this?
How much is this?
0
How much is this?
How much is this?
+3
How would you describe what
happens here?
How would you describe what
happens here?
How would you describe what
happens here?
(+4) +
How would you describe what
happens here?
(+4) + (-2) =
How would you describe what
happens here?
(+4) + (-2) = +2
Task A
1. Match each diagram with one of the calculations,
write the calculation in the space beneath the
diagram.
2. Write the answer to the calculation after the equals
sign.
3. Check that the answer matches what you see in the
drawing.
(+5) – (+2) =
(+5) + (+2) =
(+5) + (-2) =
(-5) – (-2) =
(-5) + (-2) =
(-5) + (+2) =
Task B
Draw diagrams to represent the following calculations.
(-2) + (-4) =
(+ 4) + (-5) =
(+ 7) + (-3) =
(+8) - (+ 3) =
(-8) + (- 3) =
(-6) + (+3) =
Task B
Now draw diagrams to represent your own calculations.
What about this?
+2
What about this?
What do we get when we
take away a negative?
What about this?
(+2) -
What about this?
(+2) – (–1) =
What about this?
(+2) – (–1) = (+3)
Another example
Another example
+1
Another example
(+1) – (–2)
Another example
(+1) – (–2) = +3
How can I draw (+2) – (+5)?
How can I draw (+2) – (+5)?
Another way of thinking of (+2)…
How can I draw (+2) – (+5)?
And another...
How can I draw (+2) – (+5)?
And another...
Do you agree that this is still (+2)?
How can I draw (+2) – (+5)?
How can I take away (+5)?
How can I draw (+2) – (+5)?
(+2) – (+5) =
How can I draw (+2) – (+5)?
(+2) – (+5) = (-3)
Task C
1. Match each diagram with one of the calculations,
write the calculation in the space beneath the
diagram.
2. Write the answer to the calculation after the equals
sign.
3. Check that the answer matches what you see in the
drawing.
(+2) - (+5) =
(-2) - (-5) =
(+5) - (-2) =
(-2) - (+5) =
(+2) - (-5) =
(+2) - (+5) =
Extension Task
Split your page into three columns, like below.
For each statement decide if the statement is sometimes
true, always true or never true.
You must give reasons for your answers.
Always True
Sometimes True Never True
Answers (1)
Calculations (2)
Look back at your answers
for the starter activity.
Do you want to change any
of your answers?
Using a number line
(+8) – (+3)=
Using a number line
(–3) + (+8)=
Using a number line
(+8) – (–3)=
Using a number line
(–8) + (–3)=
Using a number line
(+3) – (+8)=
Using a number line
(–8) – (–3)=