Challenge Level

Thank you to those who submitted solutions to this problem. There were plenty of opportunities to practise calculations, and also to share different strategies.

Courtenay and Max from Ickford Combined School looked at the set of fifteen cards, as did Ms Bean's Math Whizzes from Sylvan Park. They both noticed that the answers are numbers between $21$ and $35$, and could be arranged in ascending or descending order. Courtenay and Max explained how they sorted their cards:

First we sorted them into the five time tables and the two times table. Then we sorted them into ones that have a digit that is a two or three and ones which have both. All cards were used.Maya, Max, Josh, Amy, Dylan and Imi from Weeke Primary solved the set of twenty cards:

All of the answers when put in order from smallest to largest go from $110$ to $129$.$10\times$ $5$th prime number = $110$

$37\times3 = 111$

$16\times 7 = 112$

$191 - 78 = 113$

$57\times2 = 114$

$23\times5 = 115$

$29\times4 = 116$

$13\times9 = 117$

twice $59$ = $118$

$17\times7 = 119$

$8\times15 = 120$

square of the $5$th prime number = $121$

double $61$ = $122$

$41\times3 = 123$

$4\times31 = 124$

$5$ squared x $5$ = $125$

$7\times18 = 126$

$216 - 89 =127$

$2$ squared x $2$ squared x $2$ squared x $2$ = $128$

$3\times43 = 129$

Well done, and thank you very much to all who submitted solutions!