We included **HMH Into Math Grade 4 Answer Key PDF** **Module 21 Review **to make students experts in learning maths.

## HMH Into Math Grade 4 Module 21 Review Answer Key

**Vocabulary**

Question 1.

Draw a line to the correct vocabulary term.

Answer:

**Concepts and Skills**

**Write the time shown on the clock.**

Question 2.

The time is __________.

Answer:

The time is **6:40**.

Explanation:

The hours hand is in between 6 and 7. The minute hand is at 8 which implies 40 minutes(8 x 5). So, the time shown on the above clock is 6:40.

Question 3.

The time is __________.

Answer:

The time is **1:55**.

Explanation:

The hours hand is in near to 2. The minute hand is at 11 which implies 55 minutes(11 x 5). So, the time shown on the above clock is 1:55.

**Use Tools** Complete. Name the strategy or tool you will use to solve the problem, explain your choice, and then find the answer.

Question 4.

4 hours = __________ minutes

Answer:

We know that 1 hour is equal to 60 minutes.

1 hour = 60 minutes

4 hours = ? minutes

Multiply 4 with 60 the product is equal to 240 minutes.

So, Four hours is equal to **240 minutes**.

Question 5.

9 minutes = _________ seconds

Answer:

We know that 1 minutes is equal to 60 seconds.

1 minute = 60 seconds

9 minutes = ? seconds

Multiply 9 with 60 the product is equal to 540 minutes.

So, Nine hours is equal to **540 seconds**.

**Identify which amount of time is longer.**

Question 6.

4 hours or 200 minutes

_________ is longer.

Answer:

We know that 1 hour is equal to 60 minutes.

1 hour = 60 minutes

4 hours = ? minutes

Multiply 4 with 60 the product is equal to 240 minutes.

Four hours is equal to **240 minutes**.

So, **4 hours** is longer.

Question 7.

3 hours or 190 minutes

__________ is longer.

Answer:

We know that 1 hour is equal to 60 minutes.

1 hour = 60 minutes

3 hours = ? minutes

Multiply 3 with 60 the product is equal to 180 minutes.

Three hours is equal to **180 minutes**.

So, **190 minutes** is longer.

Question 8.

The train leaves County Station at 8:10:45 a.m. and travels for 1 hour 40 minutes 25 seconds to Center Station. The train stays at Center Station for 4 minutes 20 seconds. At what time does the train leave Center Station?

(A) 9:54:55 a.m.

(B) 9:54:90 a.m.

(C) 9:55:30 a.m.

(D) 9:55:40 a.m.

Answer:

Explanation:

The train leaves County Station at 8:10:45 a.m. and travels for 1 hour 40 minutes 25 seconds to Center Station.

To calculate at what time the train arrived at Center Station. We have to add start time with elapsed time then we get the end time.

8 hours 10 minutes 45 seconds + 1 hour 40 minutes 25 seconds = 9 hours 50 minutes 70 seconds

Here, we have to regroup the seconds as minutes. We know that 1 minute is equal to 60 seconds. The time 9 hours 50 minutes 70 seconds is regrouped as 9 hours 51 minutes 10 seconds.

The train arrived Center Station at **9:51:10 a.m.**

The train stays at Center Station for **4 minutes 20 seconds.**

9 hours 51 minutes 10 seconds + 4 minutes + 20 seconds = 9 hours 55 minutes 30 seconds

The train leaves Center Station at **9:55:30 a.m.**

Question 9.

Beth uses a digital watch to time her exercise one morning. She starts her run at 8:31:46 a.m. Her run ends at 9:22:17 a.m. How long does Beth run?

Answer:

Beth starts her run at 8:31:46 a.m. Her run ends at 9:22:17 a.m.

Elapsed time = End time – Start time

Elapsed time =9:22:17 a.m. – 8:31:46 a.m.

First subtract the seconds, next subtract minutes, and last subtract hours.

Here 46 seconds is greater than 22 seconds and 31 minutes is greater than 22 minutes. Regroup 1 hours as 60 mins and 1 minutes as 60 seconds. So end time 9:22:17 a.m. is regrouped as **8:81:77 a.m.
**Elapsed time = 8:81:77– 8:31:46

Elapsed time =

**0:50:31**

Beth runs for

**50 minutes 31 seconds**.

Question 10.

Merrel has a record of her times for each obstacle in a course. Complete the table to show the start time, end time, and elapsed time of each obstacle.

Answer:

Explanation:

For First obstacle we have to calculate end time.

End time = Start time + Elapsed time

= 00:00:08 + 00:02:31

= 00:02:39

The end time for First obstacle is **00:02:39**.

For Second obstacle we have to calculate Elapsed time.

Elapsed time = End time – Start time

= 00:05:14 – 00:02:50

First subtract the seconds, next subtract minutes, and last subtract hours.

Here 50 seconds is greater than 14 seconds. Regroup 1 minutes as 60 seconds. So end time 00:05:14 a.m. is regrouped as **00:04:74 a.m.**

= 00:04:74 – 00:02:50

= 00:02:24

The Elapsed time for Second obstacle is **00:02:24**.

For Third obstacle we have to calculate Start time.

Start time = End time – Elapsed time

= 00:08:22 – 00:02:57

First subtract the seconds, next subtract minutes, and last subtract hours.

Here 57 seconds is greater than 22 seconds. Regroup 1 minutes as 60 seconds. So end time 00:08:22 a.m. is regrouped as **00:07:82 a.m.**

= 00:07:82 – 00:02:57

= 00:05:25

The Start time for Third obstacle is **00:05:25**.

Question 11.

Bonnie is 4 feet 9 inches tall. A shelf is at a height 10 inches more than Bonnie’s height. Which is the height of the shelf?

(A) 4 feet 1 inch

(B) 5 feet 9 inches

(C) 59 inches

(D) 67 inches

Answer:

Explanation:

Bonnie is 4 feet 9 inches tall. Convert Bonnie height into inches. We know that 1 feet is equal to 12 inches.

Multiply 4 with 12 the product is equal to 48 inches.

4 x 12 = 48 inches

Add 48 inches with 9 inches the sum is equal to 57 inches.

A shelf is at a height 10 inches more than Bonnie’s height.

Add 57 inches to 10 inches the sum is 67 inches.

57 + 10 = 67 inches

The height of the shelf is **67 inches**.

Question 12.

Sasha walks 1,225 meters. Corey walks 2\(\frac{1}{2}\) kilometers. Gen walks twice as far as Corey. How much farther than Sasha does Gen walk? Explain.

Answer:

Sasha walks **1,225 meters**.

Corey walks 2\(\frac{1}{2}\) kilometers. Convert kilometers into meters. We know that 1 kilometer is equal to 1000 meters.

1/2 kilometer = 500 meters

1 kilometer = 1000 meters

2 kilometers = 2,000 meters

2\(\frac{1}{2}\) kilometers = 2,500 meters

So, Corey walks **2,500 meters**.

Gen walks twice as far as Corey.

Multiply 2 with 2,500 the product is equal to 5,000 meters.

2 x 2,500 = 5,000 meters

Gen walks **5,000 meters**.

5,000 – 1,225 = 3,775 meters

Gen walks** 3,775 meters** farther than Sash.