What is the role of the decimal point in a number?

It separates the whole number part from the fractional part in decimal notation.

The screw measures ___ cm, which is equal to 2 whole centimeters plus 7 tenths of a centimeter.

2.7

What does 4/10 represent in terms of tenths?

Four-tenths, which indicates 4 out of 10 equal parts.

Convert 78 mm into cm.

78 mm = 7.8 cm

True or False: 0.4 is equal to 0.40

Yes, 0.4 and 0.40 are equal because adding a zero after the last digit in a decimal doesn’t change its value.

In the number 9.246, which digit is in the thousandths place?

6 is in the thousandths place 

Estimate the sum: 3.82 + 5.67 ≈ ______

3.82 ≈ 4 and 5.67 ≈ 6
Estimated sum ≈ 4 + 6 = 10

I am a decimal with 2 digits. My tenths digit is twice the hundredths digit. I am more than 0.2 but less than 0.3. Who am I?

Tenths = 2

Hundredths = 1, because
2 = 2 × 1

0.21

Which of the following is equal to 0.1?
A) 1/10
B) 10
C) 1/100
D) 100/100

• 0.1 means one-tenth, which is the same as saying 1 part out of 10.

• The fraction 1/10 represents one-tenth, so 0.1 is equal to 1/10.

So, the correct answer is A) 1/10.

Which is the smallest: 4.5, 4.05, 4.005, 4.050, 4.50?

4.005 is the smallest because it has the smallest value in the thousandths place.

A ribbon is 11.39 cm long. How many hundredths of a cm is this?

11.39 cm = 11 + 39/100

 = 1100/100 + 39/100 

= 1139/100 cm 

= 1139 hundredths of a cm

True or False: 4.39 is read as “four point thirty-nine.”

False.

 Decimals are read digit-by-digit: 4.39 is “four point three nine”.

Which is longer: a 3.9 cm pin or a 4.7 cm nail?

Compare: 3.9 cm (3 + 9/10) < 4.7 cm (4 + 7/10). The nail is longer

A sequence is 3.9, 4.2, 4.5, ?.

 What is the next term?

a) 4.7

b) 4.8

c) 4.9

d) 5.1

Pattern: +0.3 

(3.9 + 0.3 = 4.2, 4.2 + 0.3 = 4.5). 

Next: 4.5 + 0.3 = 4.8. Answer: b) 4.8

True or False: Misreading 0.39 mg as 3.9 mg can be dangerous in medicine.

True. 3.9 mg is 10 times 0.39 mg, and such errors in dosage can be harmful.