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Course: Praxis Core Math > Unit 1
Lesson 2: Number and quantity- Rational number operations | Lesson
- Rational number operations | Worked example
- Ratios and proportions | Lesson
- Ratios and proportions | Worked example
- Percentages | Lesson
- Percentages | Worked example
- Rates | Lesson
- Rates | Worked example
- Naming and ordering numbers | Lesson
- Naming and ordering numbers | Worked example
- Number concepts | Lesson
- Number concepts | Worked example
- Counterexamples | Lesson
- Counterexamples | Worked example
- Pre-algebra word problems | Lesson
- Pre-algebra word problems | Worked example
- Unit reasoning | Lesson
- Unit reasoning | Worked example
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Rational number operations | Lesson
What are rational number operations?
include , , and .
For integers and decimals, we can rely on our calculators to add, subtract, multiply, and divide them. However, basic calculators can't give us answers in fractions. Therefore, we need to be able to perform fraction operations by hand.
What skills are tested?
- Writing equivalent fractions
- Multiplying fractions
- Dividing fractions
- Adding and subtracting fractions
- Performing operations on a mix of integers, fractions, and decimals
How do we multiply fractions?
The product of two fractions is equal to the product of their numerators divided by the product of their denominators.
How do we divide fractions?
Dividing by a fraction is equivalent to multiplying by the of that fraction.
How do we add and subtract fractions?
To add and subtract fractions, we must:
- Find a .
- Write the equivalent form of each fraction using the common denominator.
- Add or subtract the numerators while retaining the common denominator.
What about fractions mixed with decimals?
When working with a mix of fractions and decimals, convert the numbers based on the format of the choices.
- If the choices are presented as fractions, convert decimals to fractions.
- If the choices are presented as decimals, convert the fractions to decimals.
- Convert mixed numbers to either decimals or improper fractions.
Your turn!
Things to remember
Convert to before operating.
Simplify the result if necessary.
When working with a mix of fractions and decimals, convert the numbers based on the format of the choices.
Want to join the conversation?
How do I know how to set a problem up? On the last question, I converted the decimal into the correct fraction but I thought "of" was asking for division and not multiplication.(14 votes)
A general rule of thumb when working with fractions, "of" means to multiply.(14 votes)
- Hello, what does the plus sign with a line under it mean in the last example given?(6 votes)
It is just plus or minus. Shows the operation works on subtraction and addition.(9 votes)
- If its a decimal like 0.7 is it always out of 10?(4 votes)
the place value to the right of the decimal is the tenths place, representing the value of the digit in the place as being a value out of 10(5 votes)
- This is so kai cenat W rizzy W chat W chat(3 votes)
what is your name(1 vote)
why do we do this(1 vote)- I need help this is unhelpful i am just over it(0 votes)
- What do you need help with?(4 votes)
when dividing fractions do you always have flip the fraction on the right side to figure out the problem? I hope that makes sense.
Thank you!(0 votes)
Yes. Think "Stay. Switch. Flip" The first fraction stays as it is. The division switches to multiplication. Lastly flip the second fraction by using the reciprocal. (Don't forget you have to change all mixed numbers to fractions FIRST before doing these 3 steps.)(2 votes)