Algebra.
With algebra, all they have done is take a number out and give you a letter instead. Think of it as a puzzle. You have to work back through the question to work out which number we took out.
Step 1: like terms
If I give you this: a+7=10 you know straight away that the a is really the number 3.
If I give you this: 3a+1a=20 what I am really telling you is that 4a=20 (and hopefully you realise that the a is really the number 5).
If I give you this: 7a-3a=16 what I am really telling you is that 4a=16
(and hopefully you see that this time 'a' is really 4).
Step 2: Balancing it out
No matter if you are doing algebra or something else that equals sign means that whatever is one side has to match the answer to the other. Forget the algebra just for now whilst I show you with just numbers!
4 + 7 = 20 – 9
This is true because if you solve it…4 + 7 = 20 – 9
11 = 11
That should help you understand how to solve the infamous question of what number is that letter worth?
If I said 2a + 5 = 35 you know you need to find out what ‘a’ is.
Whenever you do algebra get rid of the numbers that are on their own.
With this one the 5 is on its own so you can get rid of it BUT BUT BUT…
Wait a moment!
If we were adding the 5 the way to get rid of it is to do the opposite.
So we need to take 5 away from the question
DON’T FORGET TO DO THE SAME TO BOTH SIDES OF ATHST EQUALS SIGN SO THAT THEY STILL MAKE SENSE!
So we started with 2a+5=35
Take that 5 away from both sides and we get…
2a=30
So now we just need to work out what 1a is.
REMEMBER that in algebra you are lazy and 2a really means 2xa
The opposite of multiplication is………………………….division
We had 2a, divide it by 2 and you get 1a
DO THE SAME TO BOTH SIDES!
2a=30
Divide by 2
1a=15!
With algebra, all they have done is take a number out and give you a letter instead. Think of it as a puzzle. You have to work back through the question to work out which number we took out.
Step 1: like terms
If I give you this: a+7=10 you know straight away that the a is really the number 3.
If I give you this: 3a+1a=20 what I am really telling you is that 4a=20 (and hopefully you realise that the a is really the number 5).
If I give you this: 7a-3a=16 what I am really telling you is that 4a=16
(and hopefully you see that this time 'a' is really 4).
Step 2: Balancing it out
No matter if you are doing algebra or something else that equals sign means that whatever is one side has to match the answer to the other. Forget the algebra just for now whilst I show you with just numbers!
4 + 7 = 20 – 9
This is true because if you solve it…4 + 7 = 20 – 9
11 = 11
That should help you understand how to solve the infamous question of what number is that letter worth?
If I said 2a + 5 = 35 you know you need to find out what ‘a’ is.
Whenever you do algebra get rid of the numbers that are on their own.
With this one the 5 is on its own so you can get rid of it BUT BUT BUT…
Wait a moment!
If we were adding the 5 the way to get rid of it is to do the opposite.
So we need to take 5 away from the question
DON’T FORGET TO DO THE SAME TO BOTH SIDES OF ATHST EQUALS SIGN SO THAT THEY STILL MAKE SENSE!
So we started with 2a+5=35
Take that 5 away from both sides and we get…
2a=30
So now we just need to work out what 1a is.
REMEMBER that in algebra you are lazy and 2a really means 2xa
The opposite of multiplication is………………………….division
We had 2a, divide it by 2 and you get 1a
DO THE SAME TO BOTH SIDES!
2a=30
Divide by 2
1a=15!