Daily 30 Seconds - Sep 30

Click 'Start' to see the number you're starting with, and then follow the instructions until you get to the end.

Easy

−1

×4

−12

HALVE

+7

×5

−13

÷2

+16

?

Copyright © Kevin Stone

Medium

×5

+8

x 2/9

HALVE

SQUARE

DOUBLE

+2

x 1/2

×3

?

Copyright © Kevin Stone

Hard

×3

x 25%

÷12

+2

x 21/5

+1

x 21/2

×5

x 10%

?

Copyright © Kevin Stone

Notes

All daily items change at midnight GMT (it is roughly 10:31 AM GMT). Change.

• HALVE   divide by 2 (e.g. 10 ÷ 2 = 5)
• DOUBLE  multiply by 2 (e.g. 10 x 2 = 20)
• SQUARE  times by itself (e.g. 10 x 10 = 100)
• CUBE    times by itself twice (e.g. 10 x 10 x 10 = 1,000)
• x ³/₅   find three fifths (e.g. ¹/₅ of 15 = 3, so ³/₅ = 9)
• x 2¹/₃  find two and a third (e.g. 2 ¹/₃ of 15 = 2 x 15 + 5 = 35)
• x 10%   find 10% (e.g. 10% of 80 = 8)
• √       find the square root (e.g. the square root of 100 is 10)

I have deliberately chosen not include the answers. You can use a calculator to see the value at each stage of the calculation.