By second grade, most students can count by 1s, 2s, 5s, and 10s, up to at least 200. We can make it easy for them to "tell time" by expanding this to include counting by 15s, 20s, and 30s, as well as counting by 10s starting at any number (7, 17, 27...).

When you stop and think about it, all points on the clock can be reached quickly by counting various combinations of 30, 20, 15, 10, 5, and 1.

When students are taught these counting skills before they deal with clocks, learning how to tell time is a very straightforward process. Without these skills, it's quite a chore.

Here's a way to teach students these skills:

• Counting by 10s starting at any number goes like this: start at 23: twenty-three (23), thirty-three (33), forty-three (43)... as though you are just counting by 10s, except that you say the three. So, counting by 10s starting at 37 becomes thirty-seven, forty-seven, fifty-seven...

• Counting by 15s can be done by counting by 10 and then counting by 5: 15 + 15 = (15 + 5) + 10 = 20 + 10 = 30. 30 + 15 = (30 + 10) + 5 = 40 + 5 = 45. 45 + 15 = (45 + 5) + 10 = 50 + 10 = 60.

• Counting by 20s is almost the same as counting by 2s: 0, 20 (twenty), 40 (forty), 60 (sixty), 80 (eighty)...

• Counting by 30s should be presented after the child can count by 3s. Counting by 3s is similar to counting by 2s. Counting by 2s can be explained as, "Say the number, skip the next number, say the number..." Then counting by 3s becomes: "say a number, skip the next two numbers..." Now counting by 30s becomes: 0, 30 (thirty), 60 (sixty), 90 (ninety)...

With the help of parents or teachers, telling time can be introduced to a student as early as kindergarten. The sooner students learn to count quickly using the above methods, the sooner they'll be using terms like "quarter till" and "half past."

- Larry Martinek