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This is page 1 of 1 (This thread has 11 messages.)
The Q's are the lengths of the sides of a cube. The volume of the cube is 1131cm3
Do we win a prize?
Not for just pressing the cube root button on your calculators...lol
Ah, but I didn't (I couldn't find it )<makes own chufty badge>
No calculator allowed!Seriously.Y6 maths. I now recognise DS is supposed to try estimation to get there- recognising it's not 10 cubed, so trying 11.<snatches chufty badge back>
If you're using estimation you can see immediately that 1331 > 1000Cube root of 1000 = 10, Therefore cube root of 1331 >10If you look at:0^3 = 01^3 = 12^3 = 83^3 = 274^3 = 645^3 = 1256^3 = 2167^3 = 3438^3 = 5129^3 = 729As only 1^3 ends in a 1, the answer must end in a 1 too.As 20^ 3 =8000, The answer must be between 10 and 20 and end in a 1Therefore the answer is 11.
I didn't understand any of that. It is just 11.
Agree. Doesn't need a calculator. Clearly must be more than 10 as 10 cubed is 1000Since 1 cubed is 1, worth trying 11.11 x 11 = 121 and 121 x 11 = 1331 (neither of which are difficult calculations)I don't think you need notice, as DeWe does that it must end in 1. That requires you to work out all those other cubes.
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