Math: Addition - Extra Study Help
Some Helpful Tools
Addition Pairs
1 + 1 = 2
2 + 2 = 4
3 + 3 = 6
4 + 4 = 8
5 + 5 = 10
(back of card 2)
81 Addition Facts
Try to familiarize yourself with the following addition facts. Review these facts everyday until you can write them without having to think about them.
Below is a detailed look at place value. Let's look at a seven-digit number:
2,192,742
If you break down this number using a value chart, it will be written like this:
millions
ones
thousands
2 , 1 9 2 , 7 4 2
Zero is used as a placeholder.
Therefore, the number 53, 072,193 will be read as:
"fifty-three million, seventy-two thousand, one hundred ninety-three"
When the zero is placed after the 2, the number will be written as:
53,720,193.
"fifty-three million, seven hundred twenty thousand, one hundred ninety-three."
This number will read:
"two million, one hundred ninety-two thousand, seven hundred forty-two"
Once you've learned the sums for addition pairs, you can solve any addition
problem.
Let's look at the addition pairs again:
When adding the number 9 to a one digit addend, remember that both numbers are under 10. Therefore, the sum will fall between 10 and 18.
9 + 1 = 10 9 + 6 = 15
9 + 2 = 11 9 + 7 = 16
9 + 3 = 12 9 + 8 = 17
9 + 4 = 13 9 + 9 = 18
9 + 5 = 14
Notice how the number in the ones place (boldface print) of the sum is one
number less the number you are adding to 9. Hint: 0 is less than 1, 1 is less than 2,
2 is less than 3, and so on.
Example 1: 9 + 6 =
Estimating can help you solve the following problem.
Example: 37 + 52 =
You can round to the nearest ten, hundred, thousand, etc. In this case, 
since the addends are two-digit numbers, round to the nearest ten.
40 + 50 = 90
Hint: Remember, when you have a number in the ones place that is 5 or above,
round up to the nearest ten. When you have a number that is 4 or less, round down to the nearest ten. For example: 12 rounds down to 10. 16 rounds up to
20.
Does 37 + 52 equal a sum of about 90? Let's see: 37 + 52 = 89
If you round 89 to the nearest ten, you will get 90.
To help you remember the sums for these addition pairs, follow the steps below:
2 + 2 =
4
(front of card 1)
(back of card 1)
(front of card 2)
1
2
1 + 1 =
1
2
2
Once you have finished, place all of the strips containing the addends in order
on the left side as shown above.
Mix up the strips containing the sums and place them on the right side as
shown above.
The goal is to place the sums next to their appropriate addends.
When you are finished, turn your strips over. If the numbers on the back
match, then your answers are correct. If not, keep trying until you have
reached your goal.
(back of card 3)
3 + 3 =
6
(front of card 3)
3
3
And so on...
Place Value
hundreds tens ones
Estimation
hundreds tens ones
hundreds tens ones
6 + 6 = 12
7 + 7 = 14
8 + 8 = 16
9 + 9 = 18
a.
Write the addition pairs on strips of 3 x 1 inch typing paper or construction
paper. If you use construction paper, use two different colors. One color will
contain the addends, and the other color will contain the sums.
Flip the strips over and number the backs as shown below.
For example:
b.
c.
d.
e.
To find the sum, remind yourself that 5 + 5 = 10. Notice that the addend 4 is 1 number less than 5. Therefore, 10 take away 1 equals 9. So, 5 + 4 = 9.
To find the sum, remind yourself that 8 + 8 = 16. Notice that the
addend 3 is 5 numbers less than 8. Therefore, 16 take away 5 equals 11.
So, 8 + 3 = 11.
To find the sum, remind yourself that 6 + 6 = 12. Notice that the addend 7 is 1 number more than 6. Therefore, 12 + 1 equals 13.
So, 6 + 7 = 13.
Example 1: 5 + 4 =
Example 2: 8 + 3 =
Example 3: 6 + 7 =
1 + 1 = 2
2 + 2 = 4
3 + 3 = 6
4 + 4 = 8
5 + 5 = 10
6 + 6 = 12
7 + 7 = 14
8 + 8 = 16
9 + 9 = 18
To find the sum, begin by saying that 1 less than 6 is 5.
Therefore, 9 + 6 = 15.
Example 2: 9 + 8 =
To find the sum, begin by saying that 1 less than 8 is 7.
Therefore, 9 + 8 = 17.
