We included **HMH Into Math Grade 4 Answer Key PDF** **Module 21 Solve Problems with Time and Measurement **to make students experts in learning maths.

## HMH Into Math Grade 4 Module 21 Answer Key Solve Problems with Time and Measurement

How much time do you spend on the bus?

Imagine you ride a bus to school every day. The clocks below show the times in the morning that you are picked up at home and dropped off at school.

Morning Bus Ride to School

Pick up: ________

Drop off : __________

Write the time below each clock. What is the total amount of time you spend on the bus going to school?

Answer:

Pick up: **8:24 a.m.**

Drop off : **8:53 a.m.
**Explanation:

The pick up time is 8:24 a.m. and the drop off time is 8:53 a.m. The time difference between 8:24 a.m. and 8:30 a.m. is 6 minutes and 8:30a.m. to 8:53 a.m. is 23 minutes. Add 6 minutes with 23 minutes the sum is equal to 29 minutes. So, the total amount of time spend on the bus going to school is 29 minutes.

**Turn and Talk**

If it takes you 2 minutes less to ride home from school than to ride to school, how many minutes would you spend on the bus riding to and from school during a 5-day school week?

Answer:

The pick up time is 8:24 a.m. and the drop off time is 8:51 a.m. The time difference between 8:24 a.m. and 8:30 a.m. is 6 minutes and 8:30a.m. to 8:51 a.m. is 21 minutes. Add 6 minutes with 21 minutes the sum is equal to 27 minutes. So, the total amount of time spend on the bus going to school is 27 minutes.

**Are You Ready?**

Complete these problems to review prior concepts and skills you will need for this module.

**Time to the Half Hour**

**Read the clock. Write the time.**

Question 1.

Answer:

The time is **11:30**.

Explanation:

The hours hand is in between 11 and 12. The minute hand is at 6 which implies 30 minutes(6 x 5). So, the time shown in the above clock is 11:30.

Question 2.

Answer:

The time is **5:30**.

Explanation:

The hours hand is in between 5 and 6. The minute hand is at 6 which implies 30 minutes(6 x 5). So, the time shown in the above clock is 5:30.

Question 3.

Answer:

The time is **2:30**.

Explanation:

The hours hand is in between 2 and 3. The minute hand is at 6 which implies 30 minutes(6 x 5). So, the time shown in the above clock is 2:30.

**Count by Twos and Fives**

**Count to find the unknown numbers.**

Question 4.

Count by fives.

20, _____, 30, 35, _______, 45, 50

Answer:

Given series is 20, _____, 30, 35, _______, 45, 50.

As we are counting by 5 we have to add 5 to the given first number which is 20.

So, the unknown number in first blank is 20 + 5 = **25**.

Likewise, after adding 5 to 35 gives 40(35 + 5).

So, the unknown number in the second blank is **40**.

The unknown numbers in the given series is 20, **25**, 30, 35, **40**, 45, 50.

Question 5.

Count by twos.

30, 32, _______, ______, 38, _______

Answer:

Given series is 30, 32, _______, ______, 38, _______.

As we are counting by 2 we have to add 2 to the given number which is 32.

So, the unknown number in first blank is 32 + 2 = **34**.

Likewise, after adding 2 to 34 gives 36(34 + 2).

So, the unknown number in the second blank is **36**.

After adding 2 to the number 38 gives 40(38 + 2).

So, the unknown number in the third blank is **40.**

The unknown numbers in the given series is 30, 32, **34**, **36**, 38, **40**.

Question 6.

Count by fives.

9, 14, 19, _____, _____, _____, _____, 44

Answer:

Given series is 9, 14, 19, _____, _____, _____, _____, 44.

As we are counting by 5 we have to add 5 to the given number which is 19.

So, the unknown number in first blank is 19 + 5 = **24**.

Likewise, after adding 5 to 24 gives 29(24 + 5).

So, the unknown number in the second blank is **29**.

After adding 5 to the number 29 gives 34(29 + 5).

So, the unknown number in the third blank is **34.
**After adding 5 to the number 34 gives 39(34 + 5).

So, the unknown number in the fourth blank is

**39.**

The unknown numbers in the given series is 9,14, 19,

**24, 29, 34, 39**, 44.

**Elapsed Time**

**Find the elapsed time.**

Question 7.

Start: 6:30 a.m.

End: 7:15 a.m.

Answer:

The elapsed time is** 45 minutes**.

Explanation:

The amount of time that passes between two given time stamps(Start time and End time) is called as elapsed time.

The given start time is 6:30 a.m. and the the end time is 7:15 a.m. The time difference between 6:30 a.m. and 7:00 a.m. is 30 minutes and 7:00 a.m. to 7:15 a.m. is 15 minutes. Add 30 minutes with 15 minutes the sum is equal to 45 minutes. So, the elapsed time is 45 minutes.

Question 8.

Start: 10:00 p.m.

End: 10:35 p.m.

Answer:

The elapsed time is** 35 minutes**.

Explanation:

The amount of time that passes between two given time stamps(Start time and End time) is called as elapsed time.

The given start time is 10:00 p.m. and the the end time is 10:35 p.m. The time difference between 10:00 p.m. and 10:30 p.m. is 30 minutes and 10:00 p.m. to 10:35 p.m. is 5 minutes. Add 30 minutes with 5 minutes the sum is equal to 35 minutes. So, the elapsed time is 35 minutes.

Question 9.

Start: 12:20 a.m.

End: 1:10 a.m.

Answer:

The elapsed time is** 50 minutes**.

Explanation:

The amount of time that passes between two given time stamps(Start time and End time) is called as elapsed time.

The given start time is 12:20 a.m. and the the end time is 1:10 a.m. The time difference between 12:20 a.m. and 12:30 a.m. is 10 minutes and 12:30 a.m. to 1:00 a.m. is 30 minutes and 1:00 a.m. to 1:10 a.m. is 10 minutes. Add 10 minutes with 30 minutes and 10 minutes the sum is equal to 50 minutes. So, the elapsed time is 50 minutes.