Transcript A balancing act - Welcome to Teacher Tools

A Balancing Act
I am learning that the answer on the left of the equals sign is
the same as the answer on the right of the equals sign.
4+3=2+5
= means they balance.
Let’s imagine a set of scales. Anita has 8 weights she can add to
both sides.
She puts 3 weights on the left hand side and then another 2.
She then puts 4 weights on the right hand side.
How many more weights must she add to the right hand side to make
it balance? 3 + 2 = ? + 4
1
3+2=1+4
Let’s try an example with larger numbers where we can’t use
scales. 103 + 24 = 105 + ?
Remember that =
means balances.
What’s on one side of
the equals sign must
balance with what’s
on the other.
Option 1: Look for a pattern.
Notice that 105 is 2 more than 103.
That means the missing number must be 2
less than 24. 22
Option 2: Add up one side.
We know that one side has 103 + 24 = 127
That means the other side must equal 127.
We already have 105 so….
105 + ? = 127
There are lots of different strategies you could use to find this
answer. 105 + 22 = 127
Now try these questions on your own.
1) 12 + 5 = 7 + ?
10
2) 16 + 3 = ? + 18
1
3) 76 + 14 = 74 + ?
16
4) 65 + ? = 69 + 14
18
5) 220 + 110 = 111 + ?
219
Click again when you have
completed each question and
the answer will be displayed.
Need some more practise? Try Pg54 of Teacher Tools Addition and
Subtraction Book Numeracy resources