You may also like

problem icon

Number Round Up

Arrange the numbers 1 to 6 in each set of circles below. The sum of each side of the triangle should equal the number in its centre.

problem icon

What Number?

I am less than 25. My ones digit is twice my tens digit. My digits add up to an even number.

problem icon

Odd Tic Tac

An odd version of tic tac toe

Grouping Goodies

Stage: 1 Challenge Level: Challenge Level:3 Challenge Level:3 Challenge Level:3

Pat has 17 sweets in her bag. Rebecca found the next solution by taking groups of five sweets away at a time - number 12 doesn't work. Why doesn't 12 work?

Alistair from Histon and Impington Infants School said:

We know that the number of sweets is odd, because she has one left over when she counts in twos but 7 does. She could have 7 sweets or she could have 17 sweets, but she can't have 12 because it is an even number. There are no other numbers under 20 that fit these rules.