
Missing
number problemsolving activities
Sum,
Difference and Product
D8:
Two whole numbers
D9: Two decimal
numbers
Two small numbers are generated, their sum, difference
and product are worked out.
Hide the two numbers, can you work out what they are
from their sum, product and difference?
Click on 'change' to generate two more numbers.
Hide the product, work out the two numbers from their
sum and difference.
Hide
the odd or even labels: is it possible to say whether
a sum, product or difference will be odd or even?
D36: Sum puzzle
Write a number in each circle so that the number in each
square equals the sum of the two numbers on either side
of it. There are many possible solutions for the square
arithmagon. The answer sheet will give one set of solutions.
D40:
Triangle puzzle
The three numbers on each side of the triangle must add
up to the red target number.


G5:
Sums
in code
'Sums'
are written in code. The letters A to J each stand for a
digit 0 to 9. Work out what digit each letter stands for
and what the 'sum' is.
Options:
1 times tables 2 to 10
2 times tables 11 to 20
3 doubles
4 half of . . .
5 differences
6 number bonds
The
activity can be used as an interactive whiteboard game
played against the clock.
Click
in a blue rectangle next to a letter in the side panel
and then click on the number you think the letter represents.
Click on the 'check' button to see how many you've got
right. The clock can shown or hidden.
Press numbers'1, 2, 3 . . . 0' on your keyboard to show
each answer in turn.
Press the space bar to show all the answers.


Use these buttons to generate a pictogram.


Use
this button to toggle between a pictogram and a bar
chart.
Click on the each row of the pictogram or each bar to
show or hide the frequency.



Use
these buttons to hide or show the buttons panel 
O1:
Distancetime graph and train timetable
A
seaside train travels along the promenade from the tower to
the lighthouse.
The train's timetable can be displayed and a distancetime
graph is drawn as the train moves.
The timetable shows the 24 hour arrival and departure times
of the train.
The graph shows the time and distance, in miles, from the
tower. Click on the 'go' button to start the journey.
The
buttons:
Click
on the 'go' button to start the journey.
Top left: show or hide the timetable.
Top middle: Show or hide the times in the timetable: click
in the timetable to show or hide individual times.
Top right: show or hide the graph.
Bottom left: replay the journey showing the graph generated.
Bottom middle: replay the journey showing the graph already
generated.
Bottom right: zoom in or out of the graph ( the graph can
be dragged left or right).

