Quick lessonMathGrade 1
Finding One More and One Less Than a Number
About this lesson
Children use a number line on the board to find the number that is one more or one less than a given number up to 20, then practise with a partner. It builds counting forward and backward and early adding and subtracting of one. You need a whiteboard, scrap paper and pencils, and it takes about 12 minutes.
- Grade
- 1
- Subject
- Math
- Time
- 12 min
- Prep
- 2 min
Objective
Students will name the number that is one more or one less than any number from 0 to 20.
Prep
2 min: draw a 0 to 20 number line on the board
Materials
- whiteboard and marker
- scrap paper
- pencils
Steps
- Point to the number line and say, "One more is the next number when we count up. One less is the number just before." Model with 7 by hopping the marker forward to 8, then back to 6.
- Say a number and give a signal, with thumbs up for one more and thumbs down for one less. Children write the answer on scrap paper and hold it up when you say "Show me."
- After each round, invite one child to hop along the number line to check. Do 6 to 8 rounds, starting with numbers under 10 and moving into the teens.
- Put children in pairs. One partner says a number and shows thumbs up or down, and the other answers. Partners switch after three turns.
- Finish by asking the whole class to call out the answers to "one less than 10" and "one more than 19."
Quick Check
Ask three children individually for one more than 14 and one less than 11, and note who answers without counting from 1.
Differentiation
Make it easier: Use only numbers from 0 to 10 and let children touch the number line to hop.
Make it harder: Cover the number line and use ten more and ten less with numbers up to 50.
Good For
- Transition time
- Morning warm-up
- Supply teacher
- Review
