Cogito
Grade 4 Math · Chapter 1 · Lesson 2
Reading and Writing Large Numbers
Thousands, ten thousands, hundred thousands.
10 problems · about 14 minutes · 4.NBT.A.2
What this lesson teaches
The child reads and writes multi-digit numbers in numerals, words, and expanded form.
- Large numbers are grouped in periods of three.
- Read one period at a time, then say its name.
- Expanded form shows what each digit is worth.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
3 problemsReview — Ten Times Bigger: In 6,283, what is the 2 worth?
Answer 200
Why It is in the hundreds place, so it is worth 200.
Review — Ten Times Bigger: Moving a digit one place to the left multiplies its value by what?
Answer 10
Why Each place is worth ten times the one to its right.
Review — Ten Times Bigger: In 8,340, what is the 8 worth?
Answer 8000
Why The thousands place.
Warm Up
Straightforward practice. Get the method working first.
3 problems60,000 + 700 + 8 in digits?
Answer 60708
Why 60,708.
What does a comma do in a large number?
Answer It groups the digits in threes.
Why Commas split a number into periods of three.
20,000 + 5,000 + 400 + 30 + 1 in digits?
Answer 25431
Why Each part in its place.
Build It Up
The same ideas with more to keep track of.
1 problemIn 87,502, what is the 7 worth?
Answer 7000
Why The thousands place.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
3 problemsHow many digits are in each period?
Answer 3
Why Look between the commas.
Writing It Down: What is 40,000 + 3,000 + 200 + 6 in digits?
Answer 43206
Why 43,206.
The Missing Tens: In 50,904, what is the 9 worth?
Answer 900
Why The 9 is in the hundreds place.