Grade 4: Expanded Form

Warm up with a few quick expanded form warm-ups on the board while the class settles, so every child starts thinking about the skill.

Expanded form writes a number as the sum of the value of each digit, so 347 becomes 300 + 40 + 7. It makes place value visible and is the bridge between reading a number and understanding what its digits are worth. Standard form is just the normal way of writing it (347). Model the method clearly, thinking aloud:

• Build the number first with base-ten blocks or place-value counters so each digit's value is concrete.
• Write each digit's value under a place-value chart: the 3 is 300, the 4 is 40, the 7 is 7.
• Add them with plus signs to make the expanded form: 300 + 40 + 7.
• Practise both directions, number to expanded form, and expanded form back to a standard number.
• Show what happens with a zero: 508 is 500 + 8 (the zero tens are left out).

Do the first few questions of the practice worksheet together, one child explaining each step. Check for understanding before releasing the class to work alone.

Students complete the worksheet independently. Hand out the three difficulty levels below so every child works at the right stretch.

Circulate and look for these, they are the usual sticking points:

• Writing the digits instead of their values (3 + 4 + 7 instead of 300 + 40 + 7).
• Including a zero place (500 + 0 + 8 instead of 500 + 8).
• Losing the place value of a middle zero when going back to standard form.

Pull the class back together. Ask one child to explain expanded form in their own words, pose a single check question everyone answers on a mini whiteboard, and name what you will build on next lesson.

Use the independent worksheet as the evidence. A child who can complete it accurately and explain one answer has met the objective; anyone who cannot needs the easier level and a short reteach next session.