Grade 4: 27 skills.

Indented means “needs the one above it first”. A skill with no indent starts from earlier grades.

Adding fractions, same denominator CCSS-M 4.NF.3

Misconceptions recognised: adding the tops and adding the bottoms.
- Line plots: totals & ranges CCSS-M 4.MD.4
- Mixed numbers CCSS-M 4.NF.3c
  
  Misconceptions recognised: subtracting mixed numbers without regrouping.
Area & perimeter formulas CCSS-M 4.MD.3

Misconceptions recognised: mixing up area and perimeter.
Area with partial squares

Misconceptions recognised: dropping the half squares; counting a half square as one.
Converting measurement units CCSS-M 4.MD.1-2
Division with remainders CCSS-M 4.NBT.6
- Multi-step story problems CCSS-M 4.OA.3
  
  Misconceptions recognised: treating every remainder the same way.
Equivalent fractions CCSS-M 4.NF.1
- Comparing any two fractions CCSS-M 4.NF.2
  
  Misconceptions recognised: comparing fractions by how far they are from one; bigger numbers mean a bigger fraction.
- Tenths & hundredths CCSS-M 4.NF.5
  - Writing fractions as decimals CCSS-M 4.NF.6
    - Comparing decimals CCSS-M 4.NF.7
      
      Misconceptions recognised: the longer decimal is bigger; the shorter decimal is bigger.
    - Money as decimals Ontario F1
Factors & multiples CCSS-M 4.OA.4

Misconceptions recognised: calling 1 a prime; every odd number is prime.
Fraction times a whole number CCSS-M 4.NF.4

Misconceptions recognised: multiplying a whole number into top and bottom.
Measuring angles CCSS-M 4.MD.5-6

Misconceptions recognised: thinking longer arms make a bigger angle; reading the protractor's other scale.
- Adding angles CCSS-M 4.MD.7
  
  Misconceptions recognised: measuring from the arm instead of the point.
- Lines, rays & angle types CCSS-M 4.G.1-2
Multi-digit multiplication CCSS-M 4.NBT.5

Misconceptions recognised: forgetting to shift the second row.
Multiplication as "times as many" CCSS-M 4.OA.1-2

Misconceptions recognised: "three times as many" as "three more".
Patterns from a rule CCSS-M 4.OA.5
Place value to 1,000,000 CCSS-M 4.NBT.1-2
- Adding & subtracting large numbers CCSS-M 4.NBT.4
  
  Misconceptions recognised: writing the carry into the answer; forgetting the carried ten; borrowing without taking one from the next column; taking the small digit from the big one.
- Comparing large numbers CCSS-M 4.NBT.2
- Rounding large numbers CCSS-M 4.NBT.3
  
  Misconceptions recognised: cutting the number off instead of rounding; rounding at the wrong place.
Symmetry CCSS-M 4.G.3

Misconceptions recognised: a diagonal of a rectangle as a line of symmetry.

Misconceptions are the rules children reach for that almost work; the names here are the research vocabulary for them. Cardinal Math watches for them as the problem is worked, not just in the answer. The guides under Help for parents walk through the common ones with examples.