Unknown Addends and Factors
4th Grade
4.N.1.7
Looking for students with great detective skills!!
What is an ADDEND?
An addend is any of the numbers being added together.
And the sum is the grand total.
What is a FACTOR?
Factors are numbers that are multiplied together to get a product.
A product is the result of multiplying factors.
Let’s review!!
3, 3, 4, and 1 are ADDENDS
6 and 5 are SUMS
Let’s review
6 x 4 = 24
24 is the PRODUCT
6 and 4 are FACTORS
Important Symbols
This is the “greater than” symbol. It tells us that the value to the left is greater than the value to the right.
100 > 98
Important Symbols
This is the “less than” symbol. It tells us that the value to the left is less than the value to the right.
100 < 120
Important Symbols
This is the “equal” symbol. It tells us that the value to the left is equal to the value to the right.
300 = 300
Let’s practice using symbols.
536 ____ 563
5,451 = 5,451
5,451 is equal to 5,451
5,451 ______5,451
400 > 40
400 is greater than 40
400 _____ 40
536 < 563
536 is less than 563
Ready for a Challenge??
Gather your problem solving skills and help me detect the correct symbol for these mathematical equations.
Try solving this inequality.
201 + 3 _______ 198 + 5
We have to determine if the equations are equal.
STEP 1 is to find the value of each side.
201 + 3 equals 204 and 198 + 5 equals 203.
These values are not equal.
204 is greater than 203 so we will insert a “greater than” symbol because 201 + 3 is greater than 198 + 5.
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What if a number is missing? Can you become a detective to find the missing number?
The equal sign in the center tells us that both values must have the same sum.
Step 1 - find the value of 45 + 7
45 + 7 = 52
Since the left side of the equal sign equals 52, we know that the right side must equal 52 as well.
Step 2 - Think, “What plus 10 equals 52?”
(You could also subtract 10 from 52. (52 - 10 = ?)
n would need to be 42 to make each side equal 52.
Give this one a try. Remember that the “less than” symbol tells us that the value on the left must be smaller than the value on the right.
We can add 35 and 4 to find the sum 39. We now need to pick a number from the list that is greater than 39 when added to 6. A good way to solve this one is using the process of elimination.
Let’s try this with multiplication.
Step 1 - Multiply 25 x 6
Step 2 - m x 2 must have the same value as 25 x 6 since there is an equal sign between the two values.
25 x 6 = 150
150 = m x 2
75 x 2 = 150
One more example...
12 x 8 = 96 We are looking for a value that is smaller than the left equation.
Since 12 is represented on each side, we can pick a number that is smaller than 8 and know that the value will be less than 96. Seven is the logical choice.
You are experts!!
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