Why do Americans traditionally score poorly on Estimation, Measurement, and Geometry?
Do you know someone that decides once a year that they are going to get into shape, so they go to the gym everyday for two weeks, maybe a month? They start to feel good and are getting into shape. Then they get bored or busy and only go once in awhile. Slowly but surely they stop going all together. Next year, they decide that they need to get into shape and the cycle begins all over again.
The way we teach math is a little like that. I would love to tell you that we have totally changed, but that is not true. We are in the process of changing. Think back to your childhood. You had Math every year. You had a unit on Geometry and another one on Measurement (unless Long Division ran long that year, then Measurement probably didn’t get taught). While the unit was being taught, you knew what perimeter was. You knew what a line of symmetry was. But six months later you needed to phone a friend if you were asked what the sum of the interior angles of an isosceles triangle equaled. Americans traditionally score poorly on these three areas of Mathematics because we devote very little time to them and the time we do devote to them occurs within units that happen very infrequently. All three of these strands are very vocabulary specific. They need to be used regularly and in a variety of contexts or the vocabulary and the skills atrophy just as quickly as the muscles of the quick fix get in shape person we used in our example.
If we want to improve in these areas, we need to integrate estimation, measurement and geometry on an everyday basis, not just a unit once a year. We need to give students an opportunity to figure out how big something is, how tall, how wide, how much it weighs. We need to give them the opportunity to estimate the answer to a problem and be happy that they came close rather than then making them actually figure out the exact answer. We need to be happy that when we ask students to estimate 29 + 32 that many of our students give us the exact answer of 61 because to them “29 was close to 30 so I just added 30 + 32 and got 62, but because I had added a 1 to 29 I now needed to take 1 away so the answer was 61” instead of saying “NO! You must round both numbers to the nearest ten so the estimate is 60!” We need to have kids build things so they are using measurement, so they are talking about shapes and size. We need to let kids do crafts like sewing, making models, building dollhouses, planning how to plant the garden, and so many other rich experiences, which are Math, but we don’t acknowledge them as such in school.
While you are waiting for the schools to change, you can give these gifts to your child by sharing the activities you do that involve measuring, estimating and geometry.
Another factor that may impact Americans performance on these strands in International Tests is the fact that we teach two measurement systems while the rest of the world focuses on just the Metric system. If you study the most recent results of the TIMMS you will see that Americans do better than the international average on fractions at the Fourth Grade level but worse on decimals. The Metric System is a Base Ten system and makes use of decimals in context. This may help to explain why Americans have more trouble than their international counterparts at the Eighth Grade level on decimals and percentages (which develop out of an understanding of decimal notation).
This is a link to the NCTM press release about the most recent TIMMS reports. When you get to the bottom of a page, click on “next page” to continue.
Improving Measurement and Geometry
Improving Measurement and Geometry in Elementary Schools (IMAGES) is an initiative of the Pennsylvania State Team of the Mid-Atlantic Eisenhower Consortium for Mathematics and Science Education at Research for Better Schools (RBS).