Cogito
Grade 2 Math · Chapter 3 · Lesson 5
Three Ways to Write a Number
Digits, words, and expanded form.
10 problems · about 13 minutes · 2.NBT.A.3
What this lesson teaches
The child writes numbers to 1,000 in numerals, in words, and in expanded form.
- A number can be written in digits, in words, or expanded.
- Expanded form shows what each digit is worth.
- All three ways mean the same amount.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
2 problemsReview — Counting to 1,000: What comes after 499?
Answer 500
Why After 499 comes 500.
Review — Skip-Counting by 5s, 10s, and 100s: Counting by 5s: 40, 45, ?
Answer 50
Why 45 and 5 more is 50.
Warm Up
Straightforward practice. Get the method working first.
4 problems400 + 70 + 5 in digits?
Answer 475
Why 400 + 70 + 5 = 475.
What is the 3 in 539 worth?
Answer 30
Why It is in the tens place, so it is worth 30.
300 + 50 + 8 in digits?
Answer 358
Why Each part goes in its place.
600 + 2 in digits?
Answer 602
Why There are no tens.
Build It Up
The same ideas with more to keep track of.
2 problems"Seven hundred thirty" in digits?
Answer 730
Why No ones at the end.
In expanded form, what is the 8 in 486 worth?
Answer 80
Why It sits in the tens place.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsWriting a Cheque: What is 200 + 60 + 4 written in digits?
Answer 264
Why 200 + 60 + 4 = 264.
Reading Aloud: What is "four hundred nineteen" in digits?
Answer 419
Why It is 419.