Missing Numbers (Addition)

IWB Resource - Missing Number This interactive whiteboard resource is useful for introducing children to the concept of having the answer but not one of the numbers in the question.  An addition is shown with an answer but not one of the numbers being added.  The “20” button generates questions with an answer below 20.  The “100” button generates numbers with an answer below 100.

There are two modes that can be toggles to control how this works.  The mode is selected by using the options card which can be toggled on by tapping the turquoise triangle at the upper left of the screen.  Interactive answers can be turned on or off.

Interactive answers off:  Just the addition is shown with the missing number covered by a “?”.  Tap help to provide a hint to the question using inverse operations.  Tap the question mark to reveal.  This mode is useful for quick question and answer sessions.

Interactive answers on:  The question mark cannot be removed.  A set of answer numbers appear which can be dragged to the “Answer Here” box appear.  Once the answer is given the tick/cross button can be pushed to check the answer. Stars appear down the right of the screen.  Each pair of stars correspond to 1 question.  One star is filled in for an answer for numbers below 20.  Two stars are filled in for answers to a question below 100.  Use these to try and get ten answers correct in a row.

The hidden number can be toggled between left and right using the toggle on the option card.  The next question generated will have the card in the new place.

Go to interactive whiteboard resource.

This resource was originally designed to be part of the Numeracy Basics app but I decided that its use is to specific for that app which is a general set of tools rather than focused activities.  This may appear on another app of resources so if you have any suggestions for that or for this IWB version please leave a comment or let me know on twitter @teacherled.

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