16. communicate and justify david says \since 1 times 1 equals 1, then 0.1 times 0.1 equals 0.1.\ do you agree? explain.
17. envision stem a gray whale traveled 152 kilometers in one day. the whale swam between 7 and 8 kilometers each hour. about how many hours did it take the whale to swim the distance? show two different ways that you can use compatible numbers to find an answer. then solve.
18. meg wants to find about how many phones the company activated in one minute. explain why meg can use 15,000÷50 to find the answer.
clear connect company
phones activated: 14,270 in 50 minutes
calls made: 59,835
text messages sent: 2,063
19. higher order thinking esters choir wants to learn a new song for the school concert in 7 weeks. the song has 3,016 lines. the choir learns an equal number of lines each day. about how many lines do they need to learn each day to learn the song in time for the concert? explain.
new song → 3,016 lines
? → 50 days
? lines each day
7 weeks is about 50 days.
assessment practice
20. mr. santiagos farm is 593 acres. he divides the farm into 32 equal parts. which is the best estimate of the number of acres in each part? 5.ns0.2.2
a 10 acres
b 20 acres
c 100 acres
d 200 acres
21. a scientist counted 3,921 total eggs in 49 sea turtle nests. each nest had about the same number of eggs. which is the best estimate of the number of eggs she counted in each nest? 5.ns0.2.2
a 800 eggs
b 100 eggs
c 80 eggs
d 10 eggs

Question

Accepted Answer

### 16.
# Explanation:
## Step1: Recall decimal - multiplication rule
When multiplying decimals, we multiply the numbers as if they were whole numbers and then count the total number of decimal places in the factors. For $0.1\times0.1$, we first consider $1\times1 = 1$. The factor $0.1$ has one decimal place, and since we have two factors of $0.1$, the product should have $1 + 1=2$ decimal places.
## Step2: Determine the product
So, $0.1\times0.1=0.01
eq0.1$.
# Answer:
No, I do not agree. $0.1\times0.1 = 0.01$ because when multiplying decimals, we consider the number of decimal places in the factors.

### 17.
# Explanation:
## Method 1:
## Step1: Use 7 km/h as the speed
We know that time $t=\frac{d}{s}$, where $d = 152$ km and $s$ is the speed. If $s = 7$ km/h, then $t_1=\frac{152}{7}\approx\frac{140}{7}=20$ hours (using compatible numbers, 140 is divisible by 7).
## Step2: Use 8 km/h as the speed
If $s = 8$ km/h, then $t_2=\frac{152}{8}=19$ hours.
## Method 2:
## Step1: Round the distance
Round 152 to 160.
## Step2: Calculate the time with different speeds
If the speed $s = 7$ km/h, $t=\frac{160}{7}\approx23$ hours. If the speed $s = 8$ km/h, $t=\frac{160}{8}=20$ hours.
# Answer:
Using compatible - numbers, if we assume a speed of 7 km/h, it takes about 20 hours ($\frac{140}{7}$), and if we assume a speed of 8 km/h, it takes 19 hours ($\frac{152}{8}$). Another way, rounding 152 to 160, if the speed is 7 km/h, it takes about 23 hours ($\frac{160}{7}$) and if the speed is 8 km/h, it takes 20 hours ($\frac{160}{8}$).

### 18.
# Explanation:
## Step1: Understand the problem
The company activated 14,270 phones in 50 minutes. To find the number of phones activated per minute, we use the formula: number of phones per minute=$\frac{\text{total number of phones}}{\text{total number of minutes}}$.
## Step2: Use compatible numbers
14,270 is close to 15,000. Using 15,000 instead of 14,270 makes the division $15000\div50$ easier to calculate mentally. Since $150\div5 = 30$, then $15000\div50=300$.
# Answer:
Meg can use $15000\div50$ because 14,270 is close to 15,000, and using 15,000 makes the division calculation easier to estimate the number of phones activated per minute.

### 19.
# Explanation:
## Step1: Identify the time and the number of lines
The choir has about 50 days (since 7 weeks is about 50 days) to learn 3,016 lines.
## Step2: Use compatible numbers
Round 3,016 to 3,000. Then, to find the number of lines per day, we use the formula: number of lines per day=$\frac{\text{total number of lines}}{\text{total number of days}}$. So, $\frac{3000}{50}=60$ lines per day.
# Answer:
They need to learn about 60 lines per day. We round 3,016 to 3,000 and divide by 50 (the number of days in 7 weeks approximately) to get an estimate.

### 20.
# Explanation:
## Step1: Use compatible numbers
Round 593 to 600 and 32 to 30.
## Step2: Calculate the estimate
The number of acres in each part is $\frac{593}{32}\approx\frac{600}{30}=20$ acres.
# Answer:
B. 20 acres

### 21.
# Explanation:
## Step1: Use compatible numbers
Round 3,921 to 4,000 and 49 to 50.
## Step2: Calculate the estimate
The number of eggs in each nest is $\frac{3921}{49}\approx\frac{4000}{50}=80$ eggs.
# Answer:
C. 80 eggs

Sovi.AI - AI Math Tutor

QUESTION IMAGE

Question

Explanation:

16.

Step1: Recall decimal - multiplication rule

Step2: Determine the product

Method 1:

Step1: Use 7 km/h as the speed

Step2: Use 8 km/h as the speed

Method 2:

Step1: Round the distance

Step2: Calculate the time with different speeds

Step1: Understand the problem

Step2: Use compatible numbers

Answer:

17.