🔢 MathLevel 1Lesson 8
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Number Patterns

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Learning Objectives

  • 1Find the rule in a number pattern
  • 2Extend a number pattern by at least two terms
  • 3Fill in the missing number in a sequence
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Mini Lesson

Numbers love patterns! When numbers follow a rule — adding the same amount each time — we call it a number pattern or sequence.

What is a pattern rule?

  • The rule tells you how much to add (or subtract) to get the next number.
  • Example: 3, 6, 9, 12 — the rule is +3 (add 3 each time).
  • Look at two numbers next to each other: subtract to find the rule.

Common patterns you know

  • +1: 17, 18, 19, 20 — counting by ones
  • +2: 4, 6, 8, 10 — counting by twos (even numbers)
  • +5: 15, 20, 25, 30 — counting by fives
  • +10: 20, 30, 40, 50 — counting by tens

Finding the missing number

  • Find the rule first, then apply it to the gap.
  • Example: 10, 20, ___, 40 → rule is +10, so missing number is 30.
Four number pattern strips showing plus 1, plus 2, plus 5, and plus 10Four colored horizontal strips each showing a four-number sequence. Blue strip: 17, 18, 19, 20 with plus 1 rule. Green strip: 4, 6, 8, 10 with plus 2 rule. Yellow strip: 15, 20, 25, 30 with plus 5 rule. Orange strip: 20, 30, 40, 50 with plus 10 rule.Common Number Patterns+117181920+1+1+1+246810+2+2+2+515202530+5+5+5+1020304050+10+10+10
Four number pattern strips showing the +1, +2, +5, and +10 rules with the step labeled above each gap.
Three steps to find the missing number in a patternA step-by-step card showing how to find the missing number in the sequence 10, 20, blank, 40 by finding the rule of plus 10 and applying it to fill the gap with 30.Find the Missing Number1020?40Step 1:Find the rule.20 − 10 = 10, and 40 − 20 = 20... rule = +10Step 2:Apply the rule to the gap.20 + 10 = 30 → the missing number is 30Step 3:Check! Does the pattern hold?10, 20, 30, 40 ✅ Yes — each step adds 10!
Three-step method for finding the missing number — find the rule, apply it to the gap, then check the whole sequence.
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Ask yourself: "What is the rule? How much is added each time?"

Vocabulary
Pattern
Numbers that follow a rule, like adding the same amount each timee.g. 3, 6, 9, 12 is a pattern.
Rule
How much you add or subtract to get the next numbere.g. The rule for 5, 10, 15 is +5.
Sequence
A list of numbers that go in ordere.g. 2, 4, 6, 8 is a sequence.
Skip count
Counting by jumps of the same size, like by 2s or by 5se.g. I skip count by 5: 5, 10, 15, 20.
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