# 180 Days of Math for Fourth Grade Day 81 Answers Key

By accessing our 180 Days of Math for Fourth Grade Answers Key Day 81 regularly, students can get better problem-solving skills.

## 180 Days of Math for Fourth Grade Answers Key Day 81

Directions Solve each problem.

Question 1.
31 + 29 = ___
31 +  29 = 60

Explanation:
Ones Place Value
1 + 9 = 10
Put the 0 in Ones place
Carry the 1 to Tens place
Tens Place Value
1 + 3 + 2 = 6
Put the 6 in Tens place

Question 2.
Is $$\frac{7}{10}$$ equal to $$\frac{7}{100}$$?
_____________________
No. Since $$\frac{7}{10}$$ is greater than the $$\frac{7}{100}$$
Explanation:
make denominator equal for $$\frac{7}{10}$$ and $$\frac{7}{100}$$
$$\frac{7}{100}$$ = $$\frac{7}{100}$$
$$\frac{7}{10}$$ = $$\frac{7}{10}$$ X $$\frac{10}{10}$$ =  $$\frac{70}{100}$$
If the denominators are the same, then the fraction with the greater numerator is the greater fraction.
Now compare $$\frac{70}{100}$$  and $$\frac{7}{100}$$. Then
$$\frac{70}{100}$$ > $$\frac{7}{100}$$. Since $$\frac{70}{100}$$ has greater numerator.
So $$\frac{7}{10}$$ is greater.

Question 3.
Divide 50 into 10 equal groups.
_____________________
5 in each group

Explanation:
Divide 50 into 10 equal groups. So 50 ÷  10 =5

Question 4.
100 ÷ 10 = ___
= 10 R 0
= 10
100 divided by 10 equals
10 with a remainder of 0
Explanation:

Question 5.
What is the first odd number before 291?
_____________________
289 is the first odd number before 291
Explanation:
a whole number that is not able to be divided by two into two equal whole numbers The numbers 1, 3, 5, and 7 are odd numbers.
286, 287 , 288 , 289 , 290 , 291

Question 6.
Fill in the missing number.
60, 54, ___, 42, 36
60, 54, 48, 42, 36
Explanation:
The above pattern is multiples of 6
6 x 6 = 36
6 x 7 = 42
6 x 8 = 48
8 x 7 = 54

Question 7.
Write the length in millimeters.

______________
450 millimeters
Explanation:
Picture showing 4.5 cm
1 cm = 100 millimeters
4.5 cm = 4.5 X 100 millimeters
4.5cm = 450 millimeters

Question 8.
2 hours = ___ minutes
2 hours = 120 minutes
Explanation:
1 hour = 60 minutes
2 hour = 2 X 60 minutes
2 hour = 120 minutes

Question 9.
A cylinder has:
____ faces
________ vertices
____ edges