Look at the balance scales on the board. Six cubes sit on one pan and six cubes sit on the other, and the beam hangs perfectly level.
What does it mean when the two pans hang level like that?
The value of a pan is how much it is worth altogether. Watch two balances on the board. Each one holds different things on the two pans, but every beam hangs level. Look for what has to be true about the two sides for the beam to stay level.
Now watch a beam that does not hang level. Get ready to say what would fix it.
Today we level the beam ourselves. There is already a value on one pan. We build a matching value on the empty pan until the beam hangs level.
The letter on the empty pan is just a stand-in for the value we do not know yet and are going to build. The loaded pan we start with shows 4 + 3, so we build a matching value on the other pan until the beam hangs level.
In your maths copy, write three true balances using the equals sign, for example 5 + 2 = 7.
Then write one statement that is not balanced, and show why it does not balance.
Now we do it the other way round. Instead of building blocks, we set the missing number ourselves and press Check to test our prediction. Each time, work out the full pan first, then set the missing number to match it.
These pans hold bigger values than before, so work carefully. We work these in order: level 8 + 5, then 9, then 7 + 6, then 6 + 6.
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