Lesson 3:
Addends are the numbers you add. For example in the equation
4+1=5, 4 and 1 are the addends.
Sum – the answer in addition.
When adding 3 numbers, add the first 2 addends first then
add their sum to third addends.
For example when solving the equation 6 + 3 + 5 = , follow
the following steps:
6 + 3 + 5 =
6 + 3 = 9
9 + 5 = 14
Finding Missing
Addends
When finding a missing addend, add the two numbers you know
first. Then, count on to reach the sum.
Example:
5 + 2 + = 15
Add 5 and 2 first:
5 + 2 = 7
7 + = 15
Count on from 7 to 15.
7 + 8 = 15
5 + 2 + 8
= 15
Lesson 4:
When you change the order of addends, it will not change the
sum. You can add numbers in any
order.
For example:
8 + 4 = 12
4 + 8 = 12
7 + 1 + 8 = 15
8 + 1 + 7 = 15
Lesson 5:
Related facts are
facts that have the same numbers.
Example: Related facts for 6,7,13 are:
6 + 7 = 13 13
– 6 = 7
7 + 6 = 13 13
– 7 = 6
Related facts must always have the same numbers and they
must be true.
When creating subtraction related facts, the largest number
goes first because we can take away from it.
When creating addition related facts, the largest number
goes last because we can add up to it.
