Adding mixed numbers word problem | Fractions | Pre-Algebra | Khan Academy

TL;DR

Learn how to add mixed numbers, including when the fraction part is not smaller than the denominator.

Transcript

Regina rode her bike 2 and 1/4 miles from her house to school and then 1 and 5/8 miles to her friend's house. How many miles did Regina ride in total? So she first rode 2 and 1/4 miles, and then she rode 1 and 5/8 miles. So the sum is the total number of miles she rode. So to take this sum, we've seen that we can add the whole number parts, because... Read More

Key Insights

• 🪜 Adding mixed numbers involves adding the whole number parts separately and then the fractions.
• 🪜 Adding fractions requires finding the least common multiple of the denominators.
• 🛩️ If the fraction part is not smaller than the denominator, rewrite it as a mixed number.

Questions & Answers

Q: How can we find the total miles Regina rode?

To find the total miles, we add the whole number parts (2 and 1) and then add the fractions (1/4 and 5/8) to get 3 and 7/8 miles.

Q: What if the fraction part is not smaller than the denominator?

In that case, we rewrite the improper fraction as a mixed number, like 9/8 as 1 and 1/8. Then, we add the whole number and the proper fraction parts.

Q: How do we add fractions with different denominators?

To add fractions with different denominators, we find the least common multiple (LCM) of the denominators. We convert each fraction to have the LCM as the denominator and then add the numerators.

Q: Why do we rewrite the improper fraction?

When adding mixed numbers, it is preferred to have the fraction part as a proper fraction. If the fraction part is improper, we rewrite it as a mixed number to maintain this convention.

Summary & Key Takeaways

• Regina rode her bike 2 and 1/4 miles to school and then 1 and 5/8 miles to her friend's house.

• To find the total miles Regina rode, add the whole number parts separately and then add the fractions.

• Adding fractions with different denominators requires finding the least common multiple.