Can you use the digits on the left of this clock along with any mathematical operations to equal the digits on the right (also with any mathematical operations)?
Which times is this possible and which times impossible?
Use the digits of the current time to make as many different calculations as possible all with different answers.
All four digits must be used and each must appear once only in each of your calculations.
Next choose a different time that you think will produce more calculations than the present time.
Topics: Starter  Arithmetic  Mixed  Number  Problem Solving  Puzzles
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how teachers could present or develop this resource? Do you have any comments? It is always useful to receive
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Previous Day  This starter is for 14 June  Next Day
09 01  0x9=0  0x1=0 
09 02  0x9=0  0x2=0 
09 03  0x9=0  0x3=0 
09 04  0x9=0  0x4=0 
09 05  0x9=0  0x5=0 
09 06  0x9=0  0x6=0 
09 07  0x9=0  0x7=0 
09 08  0x9=0  0x8=0 
09 09  90  90 
09 10  0x9=0  1x0=0 
09 11  9^{0}=1  1^{1}=1 
09 12  9^{0}=1  1^{2}=1 
09 13  9^{0}=1  1^{3}=1 
09 14  9^{0}=1  1^{4}=1 
09 15  9^{0}=1  1^{5}=1 
09 16  9^{0}=1  1^{6}=1 
09 17  9^{0}=1  1^{7}=1 
09 18  9^{0}=1  1^{8}=1 
09 19  9^{0}=1  1^{9}=1 
09 20  0x9=0  0x2=0 
09 21  √9+0=3  2+1=3 
09 22  9^{0}=1  2÷2=1 
09 23  0+9=9  3^{2}=9 
09 24  √9+0=3, 3!=6  2+4=6 
09 25  √9+0=3  52=3 
09 26  √9+0=3  6÷2=3 
09 27  0+9=9  2+7=9 
09 28  9^{0}=1  8^{2}=64, 6+4=10, 1+0=1 
09 29  0+9=9  9^{2}=81, 8+1=9 
09 30  0x9=0  0x3=0 
For more ideas see Alan Sturgess' Maths Puzzle Investigation video.
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Teacher, do your students have access to computers such as tablets, iPads or Laptops? This page was really designed for projection on a whiteboard but if you really want the students to have access to it here is a concise URL for a version of this page without the comments: Transum.org/go/?Start=June14 However it would be better to assign one of the student interactive activities below. 

Here is the URL which will take them to a related student activity.
The digital clock used on this page is adapted from code provided by Radoslav Dimov copyright © 2009.