# Digit sums and multiples

The number 18 is twice the sum of its digits

18 = 2 x (1+8)

The number 27 is 3 times the sum of its digits.

Investigate numbers which are; 4, 5, 6 ....... times the sum of their two digits.

Investigate further.....

Investigations Home

Do you have any starting points for mathematical investigations or comments about the investigations we have presented here?

A mathematical investigation is quite different to other mathematical activities. The best investigations are open ended and allow students to choose the way they work and how they record their findings. It is one of the few occasions when 'going off on a tangent' is not only acceptable but actively encouraged (within reason).

Students may ask for 'the answers' but this supposes that the activity is closed. Investigations can always be extended by varying the initial instructions or asking the question 'what if...?'. Sometimes students point out that the instructions are ambiguous and can be interpreted in different ways. This is fine and the students are encouraged to explain how they interpreted the instructions in their report.

Some students may benefit from a writing frame when producing the reports of their investigations. Teachers may suggest sections or headings such as Introduction, Interpretation, Research, Working and Conclusion or something similar.

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