Finding the Unknown Number in Addition and Subtraction

This video tutorial teaches how to find unknown numbers in addition and subtraction equations using the concept of fact families. It explains how addition and subtraction are related and provides examples to practice finding unknowns in both types of equations. The tutorial concludes with a summary of the key points covered.

What is a fact family?

• A collection of multiplication tables

• A sequence of numbers in an arithmetic progression

• A mathematical term for a set of division problems

• A group of related addition and subtraction equations

How can you find an unknown number in an addition equation?

• By subtracting a known addend from the sum

• By adding the two known numbers

• By dividing the sum by one of the addends

• By multiplying the addends

What is the unknown number in the equation 3 + ? = 10?

• 10

• 3

• 13

• 7

How do you verify the solution of an addition equation with an unknown number?

• By dividing the sum with the solution

• By adding the solution to the known number

• By multiplying the known number with the solution

• By subtracting the known number from the sum

In the equation, 14 - ? = 10, what is the unknown number?

• 4

• 24

• 6

• 10

How can you find an unknown subtrahend in a subtraction equation?

• By dividing the minuend by the difference

• By subtracting the minuend from the difference

• By subtracting the difference from the minuend

• By adding the difference to the minuend

What method is used to find the unknown number when it is the minuend in a subtraction equation?

• Subtraction

• Multiplication

• Addition

• Division

If an unknown number minus 5 equals 8, what is the unknown number?

• 5

• 8

• 3

• 13

What is the purpose of cross-checking in solving equations?

• To practice addition and subtraction skills

• To find alternative solutions

• To ensure the solution fits the original equation

• To complicate the solving process

What is the correct way to solve for an unknown number in a subtraction equation?

• By adding the difference to the known number

• By subtracting the difference from the known number

• By subtracting the known number from the difference

• By adding the known numbers