Hot Numbers

A Maths Starter of The Day

Move the numbered cards to form five 2 digit numbers which are all multiples of three.

 

Teacher: Click here for an interactive version with many different levels of challenge.

 

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Topics: Starter | Number Patterns

  • 9 Yellow, St Peters High School
  • Thursday, November 30, 2006
  • ""very good for a warm up activity" "kept mind active" from students.
    The whole class could access this and 6 students were totally engrossed for virtually the whole lesson, wanting to move to the higher levels"
  • Y5, St Nicholas
  • Thursday, December 01, 2011
  • "We found another solution: 12, 36, 90, 87, 54.
    We enjoyed it! It was fun!"
  • Mr Shepherd, St Lawrence Academy, Scunthorpe
  • Friday, December 09, 2011
  • "Interesting extension for smart groups: How many different answers are there? This can be worked systematically by groups who know the "digit sum" rule for multiples of 3.
    WORKING IT OUT (try it yourself first if you like):
    The 1, 4 and 7 can only go with a 2 or 5 or 8
    There are 6 possible pairings of these numbers.
    Each of these two digit numbers can be reversed, so there are 2 cubed combinations once the 2-digit numbers are chosen.
    The remaining digits 0,3,6,9 can be paired 3 ways.
    In each case, a pairing contains a zero, and we assums that the zero cannot go first in a 2-digit number, so there are only two possibilities once pairings are chosen.
    Overall then, the number of combinations (answers), ignoring their position on the answer grid (which would multiply the answer by 5 factorial), is:
    6 x 2cubed x 3 x 2 = 288."

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This starter has scored a mean of 3.8 out of 5 based on 40 votes.

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Answers

One solution is 12, 30, 45, 78 and 69 (but there are many more)
Computer Teacher, do your students have access to computers?
Do you have "Laptops in Lessons"?

Whether your students each have a TabletPC or share a desktop PC, this activity lends itself to eLearning (Engaged Learning).

Laptop

Here is the URL which will take them to a concise version of this page.

Transum.org/go/?Start=December2

Here's the URL which will take
them to a student version of this activity.

www.transum.org/go/?to=hot