Using crayons | Addition and subtraction within 100 | Early Math | Khan Academy

TL;DR

A math problem asks how many crayons have been used when 64 crayons at the beginning of the year decrease to 31 crayons at the end.

Transcript

• [Voiceover] Mrs. Henry's class has 64 crayons. At the end of the year only 31 crayons remain. How many crayons have been used? And they give us a picture here. So, the beginning of the year, this is 64 crayons. Six tens and four ones. One, two, three, four, five, six tens, and one, two, three, four ones. So this is 64 at the beginning of the year... Read More

Key Insights

• 🖍️ The problem involves subtracting the number of crayons used from the total at the start to find the remaining crayons.
• 💨 There are various ways to solve the problem, either through calculation or visual interpretation.
• 🖍️ The solution reveals that 33 crayons have been used.

Questions & Answers

Q: How many crayons did Mrs. Henry's class start with?

Mrs. Henry's class started with 64 crayons.

Q: How many crayons remain at the end of the year?

At the end of the year, there are 31 crayons remaining.

Q: How can we find the number of crayons used?

By subtracting the number of crayons remaining from the total at the start (64 - 31), we can find that 33 crayons have been used.

Q: How can we solve the problem using the picture?

The picture shows that there were originally six tens (60) and four ones (4). By counting the difference between the starting and ending values, we find that three tens and three ones have been used.

Summary & Key Takeaways

• The problem involves 64 crayons at the beginning of the year and 31 crayons remaining at the end.

• By subtracting the number of crayons used from the total at the start, we can find the number of crayons used.

• The calculation shows that 33 crayons have been used.