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# Relating addition and subtraction

## Video transcript

I have two green balls and three purple balls so how many balls do I have all together well it's going to be two purple sorry two green balls plus three purple balls is going to be five balls all together and you see that right over there there's five balls all together we can count them one two three four five now what if we did something a little different let's start with the five balls so we're going to start with the five balls and you can count them again one two three four five and now let's take away two let's subtract let's subtract two of these balls so let's take away one and two well then what are we left with well then we are left with one two three balls we're left with three balls and you might already see a pattern here two plus three is equal to five but if you start with five and you take away two you're going to be left with three look at how this is arranged and look at how this is arranged two plus three is equal to five but 5 minus 2 is 3 5 minus 2 is 3 and it works the other way around if I start with five if I start with five and if I were to take away three so if I subtract one two three what am I left with well I'm left with one two I am left with two so two plus three is five three plus two is five we see that there which is a which is another way of saying that 5 minus 2 is 3 or 5 minus 3 is 2 take a look at this for a little bit this is a really really important pattern or a really important idea to understand in math if you add two numbers and you get say if you're at a 2 and a 3 or you add two numbers and you get another number well if you take if you take that number and you subtract one of these you're going to get the other number