Mark’s mystery

Mark has found a three-digit number. He can read the number back to front or upside down but it is always the same.

What is Mark’s mystery number?

Find all the possibilities.

A bit fishy

The scales of a large pink fish are made up of the archs of circles with radius 2cm.

What is the area of one of the scales?

SOLUTION A bit fishy (ages 11 to 14) There is no need to use pi. The fish scale is made up of quadrants A and B, + rectangle WXYZ, minus quadrants A and B, so its area equals the area of WXYZ. The width of the rectangle = the radius of the circle, and its length is twice the radius. Its area is therefore 8cm2.

SOLUTION Mark’s mystery (ages 6 to 9) 101, 111, 181, 808, 818, 888