Question bank: Counting Natural Numbers Less Than 1,000

In school, Professor Ana's class is organizing a reading project. They plan to read books and count how many pages each one has. For this, the teacher created a table where she wrote down the number of pages of some books. For example, the book 'Pedro's Adventures' has 153 pages and the book 'Friends' Stories' has 277 pages. Professor Ana wants to know how many pages all the books have together, but she forgot to add them up. Help Professor Ana find the answer and explain how you calculated the total number of pages of the books. Remember that all the books together have less than 1,000 pages.

In school, the 2nd grade class made a big box with 100 colored pens to decorate the classroom. However, during the secret friend game, each student took more than one pen from the box without anyone seeing. At the end of the game, the teacher noticed that there were only 13 pens left in the box. Now, she wants to find out how many pens each student took. To do this, she thought of a number that, when multiplied by 13, gives a result less than 1,000, because the box cannot have more than 1,000 pens. What is the maximum number of pens each student could have taken?

In a little basket, Maria has apples to prepare the lunchbox for the week. On Monday, she puts 15 apples in the lunchbox; on Tuesday, she puts another 20 apples. On Wednesday, Maria puts 12 apples in the lunchbox, and on Thursday, she puts twice as many as she did on Monday. Maria wants to know how many apples she used throughout the week. Based on what you have learned about counting natural numbers less than 1,000, how many apples did Maria use in the lunchbox during the week? Write down how you counted the apples.

In our classroom, we have a box with several colored pencils. Upon counting, we noticed there are 23 blue pencils, 17 green pencils, and 10 yellow pencils. However, teacher Silvia challenged us to find out how many colored pencils we have in total, without counting one by one. To help solve this challenge, we can use what we have learned about numbers smaller than 1,000. Think carefully and write how you would find out the total number of colored pencils in the box, explaining what each step of your reasoning means.

Imagine you have a magic box that can hold up to 1,000 marbles. Today, your friend gave you 345 marbles to put in the box. How many more marbles can you put in the box before it is completely full?