One More, One Less: Counting On and Back

About This Resource

A free Grade 1 math worksheet on finding one more and one less than a number to 20. Students count pictures, add or take away one, use a number line and solve one-more and one-less questions. Includes a timed lesson plan, an editable Word version and an answer key.

Overview

One more means the next number when we count forward. One less means the number just before when we count back. Children use pictures and a number line to see the pattern: one more than 7 is 8, and one less than 7 is 6. They practice with numbers to 20 and explain how they know.

Resource Details

Subject: Math
Topic: One More and One Less
Category: Number Sense
File Type: PDF
File Size: 227.5 KB
Published: 14 Nov 2026
Downloads: 0

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Grade 1 (ages 6–7) 35 minutes Counting number sense number line

Student Task

Show 5 blocks. Add one. Ask: "How many now?" Take one away. Ask again.
Count forward and back on a number line together. Then do activities 1 and 2.
Children complete activities 3 to 5. Answers are in the answer key.

Classroom Use

Jump the line: children stand on a floor number line and jump one forward or one back.
Card flip: flip a number card and say one more and one less.
Tower game: build a tower, then add or remove one block and count.

Differentiation

Support: work with numbers to 10 and real objects. Challenge: find two more and two less, or work with numbers to 50.

Answer Key & Assessment

Activities 1 to 5 show whether children can find one more and one less (answer key included).

Learning Objectives

Find one more and one less than a number to 20.
Use a number line to count on and back by one.

Teacher Tips

Some children recount from 1 every time. Encourage them to start from the number they know and count one more or one back. Use real objects before moving to the number line.

What's Included

6-page printable PDF lesson pack: teacher lesson plan with timings, materials and differentiation
Key vocabulary list (5 words with meanings and examples)
Student worksheet (5 activities)
Editable Word version of the worksheet
Complete answer key (also as a separate PDF)