Guessing your housing number and age
by Len Si
(Phnom Penh, Cambodia)
Ask students to write their house number and multiply by 2; then the result plus 5; the result multiply by 50; then result plus student age; then result plus 365.
Ask student to tell their final result.
Teacher: Use the final result minus 365; then result minus 250. Therefore, the two last number is the student age; then other is house number.