Mathematics · Grade 1 · Number Sense and Quantity · Term 1

Counting by Ones to 120

Practicing counting forward and backward by ones, starting from any number within 120.

• Ontario Curriculum Expectations
• 1.NBT.A.1

About This Topic

Counting by ones to 120 is a foundational skill in Grade 1 mathematics, building upon earlier experiences with numbers. This topic focuses on developing fluency in counting both forward and backward from any given number up to 120. Students will explore number sequences, recognizing patterns that emerge as they increment or decrement by one. Understanding these patterns is crucial for developing a strong sense of number order and magnitude, which underpins more complex operations like addition and subtraction.

This skill is essential for problem-solving and serves as a building block for future mathematical concepts. When students can confidently count by ones, they can more easily visualize number lines, understand place value, and grasp the concept of adding or subtracting one. The ability to count backward is equally important, laying the groundwork for subtraction and understanding the inverse relationship between addition and subtraction.

Active learning is particularly beneficial for this topic as it allows students to physically interact with numbers and see patterns emerge. Manipulatives, number lines, and games provide concrete experiences that solidify abstract numerical concepts, making counting by ones more engaging and memorable for young learners.

Key Questions

1. Explain the pattern you notice when counting forward from 87 to 95.
2. Predict what number comes before 100 and after 100.
3. Compare counting forward to counting backward; how are they similar and different?

Watch Out for These Misconceptions

Common Misconception

Students might skip numbers or repeat them when counting, especially when transitioning between tens.

What to Teach Instead

Using a visual number line or manipulatives allows students to physically track their counting. Games that require precise counting, like the Number Line Hopscotch, help correct these errors by providing immediate feedback and reinforcing the one-to-one correspondence of counting.

Common Misconception

Difficulty transitioning from counting forward to counting backward, or understanding that backward counting is the reverse sequence.

What to Teach Instead

Activities like the Counting Train, where students build and then deconstruct the sequence, visually demonstrate the relationship between forward and backward counting. Discussing the patterns observed in both directions helps students internalize the concept.

Active Learning Ideas

Number Line Hopscotch

Create a large number line on the floor using chalk or tape, extending to 120. Students take turns hopping along the line, counting aloud as they go forward or backward from a designated starting number. The teacher calls out directions, such as 'hop forward 5 times from 37' or 'hop backward 3 times from 62'.

30 min·Whole Class

Counting Train

Students work in small groups to create a 'counting train' using connecting blocks or paper cutouts. Each student adds a number to the train, counting by ones. One student starts with a number, and the next adds the subsequent number, continuing the sequence up to 120. They can also practice counting backward by removing numbers from the end of the train.

25 min·Small Groups

Number Sequence Match-Up

Prepare cards with numbers and sequences. Students match cards that represent forward counting (e.g., 45, 46, 47) or backward counting (e.g., 83, 82, 81). Some cards can have a starting number and students must find the next three numbers in the sequence.

20 min·Pairs

Frequently Asked Questions

Why is counting by ones to 120 important for Grade 1 students?

Counting by ones to 120 is fundamental for developing number sense. It helps students understand number order, magnitude, and the relationship between numbers. This fluency is a prerequisite for addition, subtraction, and understanding place value, forming the bedrock of their mathematical journey.

How can I make counting by ones more engaging for students?

Incorporate games, songs, and movement-based activities. Using manipulatives like blocks or beads, and visual aids such as number lines, can transform rote counting into an interactive and enjoyable experience. Storytelling that involves counting can also capture their imagination.

What are common errors students make when counting by ones?

Common errors include skipping numbers, repeating numbers, or having trouble with the transition when crossing tens (e.g., saying '59, 60, 70' instead of '59, 60, 61'). Misunderstanding the sequence when counting backward is also frequent.

How does active learning support understanding of counting by ones?

Active learning allows students to physically manipulate objects, move along number lines, and participate in games. These hands-on experiences make the abstract concept of number sequences concrete. Seeing and feeling the progression of numbers helps solidify their understanding of order and patterns, making the learning process more memorable and effective.