Year 2 Number Cheatsheet

• We can count to 1000 and beyond
• Place value has three parts: hundreds, tens, and ones (e.g., 257 has 2 hundreds, 5 tens, 7 ones)
• Expanded notation shows a number broken into parts: 257 = 200 + 50 + 7
• We can add and subtract two-digit numbers, including with regrouping (carrying and borrowing)
• Multiplication is repeated addition (e.g., 3 × 4 = 4 + 4 + 4)
• We can show multiplication using arrays (rows and columns of objects)
• Division is sharing or grouping (e.g., 12 ÷ 3 = 4)
• We know fractions: halves (1/2), quarters (1/4), eighths (1/8)
• We can count money and make change using Australian coins and notes

Example 1: Understanding place value to hundreds

What does 385 mean?

Step 1: Hundreds digit: 3 (= 300)
Step 2: Tens digit: 8 (= 80)
Step 3: Ones digit: 5
Step 4: Expanded form: 300 + 80 + 5 = 385
Answer: 385 = 3 hundreds, 8 tens, 5 ones

Example 2: Adding with regrouping

Work out 27 + 18.

Step 1: Add ones: 7 + 8 = 15 (that's 1 ten and 5 ones)
Step 2: Write 5 in ones, carry 1 ten
Step 3: Add tens: 2 + 1 + 1 = 4 tens
Step 4: Answer: 45
Answer: 27 + 18 = 45

Example 3: Subtracting with regrouping

Work out 34 − 17.

Step 1: Ones: Can I do 4 − 7? No, so borrow 1 ten
Step 2: Now: 14 − 7 = 7 ones
Step 3: Tens: 3 − 1 (borrowed) = 2, then 2 − 1 = 1 ten
Step 4: Answer: 17
Answer: 34 − 17 = 17

Example 4: Multiplication using arrays

Show 4 × 3 with an array.

Step 1: Draw 4 rows
Step 2: Put 3 dots in each row
Step 3: Count: 3 + 3 + 3 + 3 = 12
Answer: 4 × 3 = 12

Example 5: Division (sharing)

Share 15 lollies equally among 3 friends. How many does each get?

Step 1: Count 15 lollies
Step 2: Give one to each friend: Friend A, B, C
Step 3: Repeat until all are shared
Step 4: Each friend gets 5
Answer: 15 ÷ 3 = 5

Example 6: Fractions

Draw a circle. Divide it into 4 equal parts and colour 1 part. What fraction is coloured?

Step 1: You coloured 1 part out of 4
Step 2: The fraction is 1/4 (one quarter)
Answer: 1/4 of the circle is coloured

• Mistake: Forgetting to regroup when adding. Fix: When ones make 10 or more, you must carry a ten to the tens column.
• Mistake: Not borrowing when subtracting. Fix: If you can't subtract the ones, borrow 1 ten from the tens column.
• Mistake: Confusing multiplication and addition. Fix: Multiplication is repeated addition. 3 × 4 means 3 groups of 4, not 3 + 4.
• Mistake: Drawing unequal parts when showing fractions. Fix: All parts must be exactly the same size.
• Mistake: Saying 4/4 is a fraction. Fix: 4/4 = 1 whole, not a fraction.

• Hundreds: Groups of 100
• Tens: Groups of 10
• Ones: Single units
• Place value: The value of a digit based on where it is
• Expanded form: Breaking a number into place value parts
• Regroup: Move a group of 10 from ones to tens (or vice versa)
• Multiplication: Repeated addition (× symbol)
• Array: Objects arranged in rows and columns
• Division: Sharing or grouping (÷ symbol)
• Fraction: A part of a whole