Cogito
Grade 4 Math · Chapter 6 · Lesson 3
Why 0.7 and 0.70 Are Equal
More digits does not mean more.
10 problems · about 15 minutes · 4.NF.C.5
What this lesson teaches
The child explains why a tenth written as hundredths is the same amount.
- 0.7 and 0.70 are the same number.
- More digits does not mean a bigger amount.
- Compare the squares, not the digits.
Warm-Up Review
From earlier lessons. Loosen up before the new work.
2 problemsReview — Hundredths: How many hundredths are in 0.09?
Answer 9
Why 0.09 is 9/100.
Review — Tenths: How many tenths are in 0.8?
Answer 8
Why 0.8 is 8/10.
Warm Up
Straightforward practice. Get the method working first.
4 problems0.2 in hundredths. How many?
Answer 20
Why 0.2 = 0.20 = 20/100.
Why is 0.70 not bigger than 0.7?
Answer They cover the same squares.
Why They are the same amount written in different units.
0.6 in hundredths. How many?
Answer 60
Why Each tenth is 10.
Is 0.50 equal to 0.5?
Answer Yes. Same squares.
Why 50 hundredths is 5 tenths.
Build It Up
The same ideas with more to keep track of.
2 problemsWhich is bigger, 0.8 or 0.75?
Answer 0.8.
Why 0.8 is 80 hundredths.
0.9 in hundredths. How many?
Answer 90
Why 9 × 10.
Stretch Yourself
Mixed problems. Work out what kind of question it is before you start.
2 problemsThe Same Amount: 0.4 written in hundredths. How many hundredths?
Answer 40 hundredths
Why 0.4 = 0.40 = 40/100.
The Comparison: Which is bigger, 0.3 or 0.25?
Answer 0.3.
Why 30 hundredths beats 25 hundredths.