Arithmetic
Map
Arrows point from what you learn first to what it opens. Right-click a concept (or press and hold it) for its lessons and stories.
- Proven to depth123
- Open
- Locked
- Comes back deeper
Learning path
In the order the concepts build on each other.
- AdditionLockedAdding puts groups together to find how many there are in all. It is counting on from the first number, or hopping right on the number line. The order doesn't matter: 3 + 5 = 5 + 3.Opens after: The number line
- MultiplicationLockedMultiplying is adding the same number again and again: 4 × 6 means 4 groups of 6, which is 24. An array of rows and columns shows that the order doesn't matter, and place value shows why times ten moves every digit one place to the left.Opens after: Addition
- SubtractionLockedSubtracting takes some away to find how many are left, or finds how far apart two numbers are - the difference. It undoes adding, and unlike adding, the order matters: 7 - 3 is 4, but 3 - 7 is -4.Opens after: Addition, Integers
- DivisionLockedDividing shares a number out fairly, or finds how many equal groups fit in it: 12 ÷ 3 = 4. It undoes multiplying. When a number doesn't share evenly, what is left over is the remainder, always smaller than the group. You can never divide by zero.Opens after: Multiplication, Subtraction
- Even and odd numbersLockedA number is even if it splits into pairs with nothing left over, and odd if one is always left. Zero is even. The last digit tells you which, because every ten pairs up. Odd plus odd is even.Opens after: Division
Connections to other domains
- Division leads to FractionsFractions
- Addition needs The number lineNumber Systems
- Subtraction needs IntegersNumber Systems