Video Transcript
Do these sums have the same
answer?
Under the question, we can see two
lines of cubes. And they both represent different
additions or sums. When we find the sum of something,
we find the total. And in our first addition, we’re
finding the sum or the total of 10 and seven. We know this because there are 10
yellow cubes, and then another seven blue cubes are added onto it.
Let’s have a look at our second
addition. What’s the same and what’s
different? Well, what’s the same is that the
addition contains the numbers 10 and seven again. Only this time they’re added
together in a different order. This time, we start with seven and
we add 10 more. So our question is asking us, is 10
plus seven the same as seven plus 10?
Can you think of a way to answer
this question without doing any adding. We could just look at the picture
and say to ourselves that the two lines of cubes are exactly the same length. So it looks like the total of the
cubes whether we add 10 and then seven or seven and then 10 is the same. But as well as looking at the
picture, it’s probably a good idea to work out the answer.
To begin with, let’s count on seven
more than 10. 10, 11, 12, 13, 14, 15, 16, 17. The sum of 10 and seven is 17. Now, let’s start with seven and
count on another 10. Seven, eight, nine, 10, 11, 12, 13,
14, 15, 16, 17. Just like we thought, both sums
have the same answer. It doesn’t matter which way around
we add two numbers together. They’ll always give the same
total. Do the sums 10 plus seven and seven
plus 10 have the same answer? Yes, they do.
