Place Value and Number Clues


Video conferencing

This week in math we’ve been working on understanding numbers using place value. We used whiteboards and place value pockets to practice. Mrs. Hamman gives us clues about a mystery number, and we try to figure out what the number is using those clues. By the time we get the last clue, we should all have the same number.

Once we knew how to find numbers this way, we decided to collaborate with another class. We did a video conference with Mrs. Fraher’s class.  They are a group of third graders who go to a school near ours, and they have been working on place value too. They gave us clues about their mystery number and we had to guess it. Then we gave them clues while they tried to guess. It was fun to see that other kids were learning the same things we were!

Do you want to try to guess a mystery number? Here are some clues:

  • It is a four-digit number.
  • The number is odd.
  • Three-fourths (or 75%) of the digits are odd.
  • The digit in the thousands place is the number of legs on an octopus.
  • The digit in the ones place is the greatest single-digit odd number.
  • The digit in the hundreds place is the quotient of 10 divided by 2.
  • When you add up the sum of the digits in the hundreds, tens and ones places, the sum is 21.
  • The digital root of the number is 2.

Can you guess our mystery number?


  1. Hi, everyone!

    Okay, you math wizards. Is my answer of 8579 correct? Did I do this correctly?
    It amazes me at what you all can do! Have you all decided what school you want to go to in Year 13?
    Hope to see you all soon,
    Mrs. Salmon

  2. Mrs. Salmon beat me to it! I love these types of number puzzles, but I had to click on the link to find out what a digital root is. You are never too old to learn something new! Thanks for keeping me on my toes. ♥ Mrs. Arnpriester

  3. What a group of mathematicians you are! Can’t wait to see future problems just like this.
    Mrs. Farris

  4. Pingback: Tips, Math Practices, and Ideas about Variables, Expressions, and Properties | 6th Grade Common Core Math

  5. Dear Mrs. Hamman’s Class,
    Well, I wanted to try this without looking first, and I got the same as Mrs. Salmon. How fun! Was it fun trying to stump the other class? I hope you all kept trying until you got the answer because in math, we always need to persevere!
    🙂 Mrs. Miller

  6. Dear Mrs.Hammen,

    I read your post.Does Kyle like you as a teacher. I saw that Mrs. Miller commented on your blog. What are you doing in math and reading?

    Your friend,

    • Dear Jacob,

      You’ll have to ask Kyle if he likes me as a teacher! In math we are learning about rounding and estimation next week. In reading we’ll be reading a story called “The Stories Julian Tells”. Thank you for your comment!

      Your friend,
      Mrs. Hamman

  7. Dear Mrs. Hamman,

    It was awesom about video confrencing. I loved it and I loved to do math questions. It was so fun doing it with Mrs. Fraher. I had a blast.

    Your student, Caitlyn

  8. Dear Jacob,

    We are having a fun time! Our class is big and fun we have computers, ipads, netbooks, and ipods.

    Your friend,

  9. Hi I’m Amelia we are really exited about quadblogging we really want your hot weather because we just have rain can we swop weather for at least a day I really like your O.R.E.O video do yo like are blog I like yours. The mosaic it is epic!!!!!!!!!!!!!!!

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