5 Strategies to Help Build Math Fluency in K–2

Helping students to develop math fluency takes more than just flash cards. It requires teaching them how to think about numbers. And while that may seem daunting, most kids enjoy sharpening their math fluency skills when they are presented with strategies that are engaging and easily understood.

In my second-grade classroom, I’ve been using the following strategies to develop math fluency, increase computation speed, and instill an understanding of numbers.

1. Skip counting

When students count upward by twos, threes, fives, or another number, that helps develop awareness of the way the number system works. I teach skip counting using a hundreds chart, a number grid with rows of 10 up to 100. In kindergarten, these charts are used to count by ones, but they’re also useful for a skip counting warm-up during a second-grade math block. I start by having the students learn how to count by 10s, then fives, and then twos. If they mastered those, I go on to threes and fours.

Students quickly begin to see repeating patterns. For example, all multiples of two are even numbers. All multiples of five end in 0 or 5.

Another way to teach skip counting is to have students sing along to “count by” songs on YouTube, such as my class’s current favorite, “Counting by Fours,” by Have Fun Teaching. This also prepares students for multiplication and addition in third and fourth grade.

2. Number lines

Have a class number line showing at least 1–100 stretching across the room above your main presentation space. You can use it to model a huge number of problems for the whole class at once: two-digit sums and differences, word problems, odds and evens, multiples of five and 10. You can put number lines at the bottom of problems on work pages, too, or provide a number line at a math station. It’s easy to put a number line in a sheet protector, along with an Expo marker for kids who find using one helpful. Number lines scaffold and reinforce student understanding of counting, and this undergirds creative solving of equations.

3. Counting on/off

In grades K–2, when students are still developing fluency with addition facts, and they don’t know facts such as 9 + 3, you can teach them how to “count on” to solve problems on their fingers. Have them start with the larger number in the addition problem, and then extend their fingers to represent the smaller number. Then they can count up on the extended fingers and reach the sum.

Here’s a five-step process students can use for adding two numbers using the count-on method:

1. Start with the larger number, held in your mind.
2. Extend fingers on your hand to represent the smaller number.
3. Starting from the bigger number, count up from that number on the fingers you’ve extended.
4. When you’ve counted all the extended fingers, write down the number you’ve counted to (the sum).
5. Check your work by starting with the sum and extending fingers for the smaller number. Count back down on these fingers and you should reach the larger number.

You can also reverse the process for subtraction by using a subtrahend (the number being subtracted from another number) of up to 10.

4. Rounding/imagine if

Teach students to round to the nearest 10 or 100 to make a problem easier to compute. For example, instead of adding 14 + 29 using the standard algorithm (or by drawing 10 bars and single units), tell them to imagine if the problem were 14 + 30. Then it becomes relatively easy: three 10s plus one 10 equals 40, and four ones gives you 44—no regrouping needed. Then, since 30 is one more than 29, they need to subtract one from the “imagine if” equation, going back from a sum of 44 to 43.

Or, when taking 49 away from 100, show them that taking 49 away is the same as taking 50 away and adding back one. This is very much a show-as-you-go strategy. Learning how to “imagine if” takes time for some students (though some will discover this strategy on their own).

These four math fluency strategies have formed a strong safety net for my students. Whenever I feel understanding breaking down, I routinely look at the problem we’re trying to solve and use one of the strategies to help more of the students understand. On test day, the students have begun to see that they can decide when to use the strategies themselves. One of the best moments in math class is when I see students get out of their chairs, wander across the room, and go to our class number line to solve a problem.

5. Friendly numbers

Friendly numbers are a mental math strategy in which students start by rounding to easily managed numbers when facing challenging problems, then reverse the rounding to get the final solution. This is related to the “imagine if” method. Friendly numbers are ones that are easy to work with, primarily multiples of 10.

For example, in my class, I might give students the problem 39 + 24. The worksheet’s layout suggests using the standard algorithm, but I point out that 39 can be made into a friendly number by adding one, resulting in the much easier 40 + 24. Just add four 10s to the two 10s in 24, resulting in 64, and then, from the sum, take back the one that was added to make 40, resulting in a final answer of 63.