by KC Yan

Estimation (or *guesstimation* as it is more commonly known in the U.S.) is a creative mathematical activity that is seldom given enough curriculum attention and time in Singapore. For the lay public, and probably for a disturbingly large proportion of local math teachers, tutors, and parents, estimation is often confused with approximation (or rounding off numbers).

Like swimming, cycling, and driving, estimating ought to be a life skill that is indispensable for all responsible citizens aiming to be numerate in our quantitative world of bloated data.

**A PSLE Estimation Routine**

In this year Singapore’s PSLE (grade 6) math paper, a routine guesstimation MCQ question has irked some parents, who “blamed” the Ministry of Education for posing an “unfair” question.

**How to Fermi-ize**

Current Singapore math textbooks are often too Puritan, not to say, boring, to contain fertile exercises that could hone students’ estimation skills. A dose of humor, without insulting or shocking the readers, will go some way in nurturing some Fermi disciples. Let’s look at eleven non-drill-and-kill guesstimation questions, which could be posed to above-average math students bored by school math.

**0. Zero Toilet Paper **

If all the toilet paper used in Singapore in an entire year were rolled out, how far would it stretch?

**1. The Trillionth Heartbeat**

**2. Pools of Eyeballs**

**3. Death Nailed by Tobacco Sticks**

© Chua Sin Yew |

A medical association claims that a cigarette smoker shortens the length of his life by 9 minutes for each cigarette smoked. A student smokes three-quarters of a pack of 20 cigarettes every day for 30 years. Excluding leap years, by how many months or years has this student cut short his life to?

**4. To Pee or Not to Pee**

**5. Length of Intestine**

**6. A Nation of Vampires—Human Blood Aplenty**

If you were to take all the human blood from all the living people in Singapore and pour it into the Singapore Indoor Stadium, how deep would it be?

**7. Zoo Poo**

**8. The Host with the Most**

How many (unfriendly and not-s0-friendly) bacteria are living on and inside you right now?

**9. ***Cash in on the Trash*

*Cash in on the Trash*

**10. ***Green Pollution*

*Green Pollution*

© Sidney Harris |

Thanks to Indonesia’s mostly incompetent politicians and corrupt businessmen, its neighbors Malaysia, Singapore, and Thailand, have unhealthily been affected by the annual haze visiting them, as a result of illegal forest burning by local farmers to save costs for their bosses.

**Estimation Skills via Gross, Illegal, or Murderous Math**

*kiasu*Singapore parents, whose children will be sitting for the PSLE oft-dreaded math paper in coming years.

*Selected Answers*2. About 73 swimming pools.