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Special 24
Age 7 to 11
Challenge Level 
This one is tough! Susannah from Headington Junior School has given it a try...
"The closest I can get is 8 times 8 which is 64, - 1 = 63.
63 + 63 = 126, 121 is 11 squared.
8.5 times 8.5 = 72.25, rounded up to 73.
72 + 72 = 144 which is 12 squared".
Sara from East Bergholt VC Primary, Suffolk
"At first I thought it was hard, but in the end it was easy!
840 + 1 = 841
841 = 29 x 29
840 x 2 = 1680
1680 + 1 = 1681
1681 = 41 x 41
So the Special Number is 840."
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