Items from tki of interest to maths teachers

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This activity invites the user to place numbers in the circles so that the total of the numbers in each circle is 3.    Adding decimals

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This activity invites the user to place numbers in the circles so that the total of the numbers in each circle is 0.   Adding with negative and positive numbers

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This activity invites the user to place numbers in the circles so that the total of the numbers in each circle is 99

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This activity invites the user to identify the counterfeit coin using a balance.   The problems increase in difficulty from 8 coins to 12 coins, where you are told whether the counterfeit coin is light or heavy.   In the challenge problems, you are given 12 coins and have to identify if the counterfeit is light or heavy.   The challenge is to complete the task in a limited number of balances.

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In this activity a balance is provided to help solve equations.   For example 3x + 5 = 8.   Using drag and drop, students can move the relevant number of x boxes and unit boxes onto the scales to create the situation which the equation models.    Then by removing boxes, it is possible to solve the equation.   The reason I like this activity is because it permits the user to experiment with putting more or weights on or removing them and seeing if the scales are still in balance.   It also encourages the user to analyse what they are doing to both sides, so that they can instruct the computer to solve the equation.

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This is a similar activity but now negatives are introduced by using balloons to lift the balance

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This applet allows the user to see what happens when you toss a coin many times.   It draws a bar chart of the proportion of times a head or tail is obtained.    The user can change the number of times the coin is tossed and the probability of a head.   It also gives other information, such as the longest run of heads obtained.

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This applet allows the user to make two triangles with some straight edges and angels.  One the triangles have been formed they the user is challenged to flip and turn the one triangle onto the other.   I found three of the situations easy to use but I wasn’t able to use SAS (segment, angle, segment) very easily, but I eventually worked it out.

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This tool allows the user to see what a fraction looks like (this includes fractions bigger than 1)

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This applet allows the user to consider equivalent fractions and as a result to solve problems related to size of fractions.   The first experience involves shading a fraction of a rectangle but once a form with comparable denominators has been found the problem is transferred onto a number line.

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Allows the user to put fractions of a square or a circle together.

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