Relationship between Addition and
Subtraction within 100.
In this video, we’re going to learn
about the relationship between addition and subtraction. Here we have 10 beads. One is green and nine are
orange. We can use the three numbers one,
nine, and 10 to make two addition facts and two subtraction facts. One plus nine equals 10 and nine
plus one equals 10. These are addition facts. We can also make two subtraction
facts. 10 take away one is nine and 10
take away nine is one. We call addition and subtraction
Inverse operations are operations
which are opposite and undo each other. So we can add one and nine to make
10 and then take it apart by taking away one to make nine. We can use the inverse operation to
help us check our calculations. In this example, we’re going to
solve the problem using subtraction and then we’re going to use the inverse addition
to help us check our answer.
The question tells us that Sophia
and Benjamin have been asked to solve 96 take away 45. Sofia solves it and gets an answer
of 51. Benjamin solves it and gets an
answer of 31. Who’s correct? Use the vertical column method to
So the question tells us to solve
96 take away 45. Using our vertical column method,
first we subtract five from six, which leaves us with one, then we work out nine
take away four, which is five. 51 is the answer that Sophia
gave. So Sophia is correct. Now we have to check our answer
using the inverse operation. What number do you add to 45 to get
96? Now instead of subtracting, we need
to add because addition and subtraction are inverse operations. We need to check if 45 add 51 equal
96. Five plus one is six and four plus
five is nine. 96 take away 45 is 51. 45 plus 51 is 96. The number we had to add to 45 to
get 96 is 51.
In this video, we’ve learned that
addition and subtraction are inverse operations and we can use the inverse to help
us check our calculations.