3.2: Topic B- Subtraction of Larger Numbers

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Topic B: Subtraction of Larger Numbers

You can find the difference between two large numbers using the basic subtraction facts you have been practicing. Always take away or subtract the number after the minus sign.

Use these steps to complete each subtraction question.

Subtract the ones from the ones.
Subtract the tens from the tens.
Subtract the hundreds from the hundreds.

Example A:

\begin{aligned}
57 \\
-26 \\
\hline
\end{aligned}

Subtract the ones from the ones. 7 ones − 6 ones = 1 one. Write the answer in line with the ones in the question.
\begin{aligned}
57 \\
-26 \\
\hline 1
\end{aligned}
Subtract the tens from the tens. 5 tens – 2 tens = 3 tens
\begin{aligned}
57 \\
-26 \\
\hline 31
\end{aligned}

The difference between 57 and 26 is 31.

Example B:

\begin{aligned}
628 \\
-524 \\
\hline
\end{aligned}

Subtract the ones from the ones. 8 ones – 4 ones = 4 ones. Write the answer in line with the ones in the question.
\begin{aligned}
628 \\
-524 \\
\hline 4
\end{aligned}
Subtract the tens. 2 tens – 2 tens = 0 tens.
\begin{aligned}
628 \\
-524 \\
\hline 04
\end{aligned}
Subtract the hundreds. 6 hundreds – 5 hundreds = 1 hundred.
\begin{aligned}
628 \\
-524 \\
\hline 104
\end{aligned}

Write the answer in line with the hundreds in the question. The difference between 628 and 524 is 104.

Exercise 1

Find the differences. Check your work using the answer key at the end of the exercise.

$\begin{align}87\\-36\\ \hline\\ \end{align}$
$\begin{align}29\\-21\\ \hline\\ \end{align}$
$\begin{align}48\\-40\\ \hline\\ \end{align}$
$\begin{align}99\\-63\\ \hline\\ \end{align}$
$\begin{align}75\\-45\\ \hline\\ \end{align}$
$\begin{align}73\\-20\\ \hline\\ \end{align}$
$\begin{align}92\\-21\\ \hline\\ \end{align}$
$\begin{align}58\\-27\\ \hline\\ \end{align}$
$\begin{align}84\\-23\\ \hline\\ \end{align}$
$\begin{align}69\\-38\\ \hline\\ \end{align}$
$\begin{align}45\\-23\\ \hline\\ \end{align}$
$\begin{align}49\\-19\\ \hline\\ \end{align}$
$\begin{align}59\\-14\\ \hline\\ \end{align}$
$\begin{align}87\\-63\\ \hline\\ \end{align}$
$\begin{align}88\\-15\\ \hline\\ \end{align}$
$\begin{align}56\\-44\\ \hline\\ \end{align}$

Answers to Exercise 1

51
8
8
36
30
53
71
31
61
31
22
30
45
24
73
12

Exercise 2

Find the differences. Check your work using the answer key at the end of the exercise.

$\begin{align}46\\-23\\ \hline\\ \end{align}$
$\begin{align}65\\-42\\ \hline\\ \end{align}$
$\begin{align}45\\-13\\ \hline\\ \end{align}$
$\begin{align}53\\-20\\ \hline\\ \end{align}$
$\begin{align}34\\-21\\ \hline\\ \end{align}$
$\begin{align}48\\-32\\ \hline\\ \end{align}$
$\begin{align}56\\-13\\ \hline\\ \end{align}$
$\begin{align}26\\-15\\ \hline\\ \end{align}$
$\begin{align}49\\-22\\ \hline\\ \end{align}$
$\begin{align}58\\-27\\ \hline\\ \end{align}$
$\begin{align}95\\-71\\ \hline\\ \end{align}$
$\begin{align}89\\-14\\ \hline\\ \end{align}$
$\begin{align}69\\-19\\ \hline\\ \end{align}$
$\begin{align}86\\-71\\ \hline\\ \end{align}$
$\begin{align}99\\-50\\ \hline\\ \end{align}$
$\begin{align}89\\-55\\ \hline\\ \end{align}$

Answers to Exercise 2

23
23
32
33
13
16
43
11
27
31
24
75
50
15
49
34

Exercise 3

Find the differences. Check your work using the answer key at the end of the exercise.

$\begin{align}23\\-11\\ \hline\\ \end{align}$
$\begin{align}53\\-21\\ \hline\\ \end{align}$
$\begin{align}32\\-20\\ \hline\\ \end{align}$
$\begin{align}77\\-32\\ \hline\\ \end{align}$
$\begin{align}32\\-21\\ \hline\\ \end{align}$
$\begin{align}38\\-15\\ \hline\\ \end{align}$
$\begin{align}33\\-13\\ \hline\\ \end{align}$
$\begin{align}92\\-30\\ \hline\\ \end{align}$
$\begin{align}94\\-23\\ \hline\\ \end{align}$
$\begin{align}54\\-42\\ \hline\\ \end{align}$
$\begin{align}74\\-33\\ \hline\\ \end{align}$
$\begin{align}88\\-72\\ \hline\\ \end{align}$
$\begin{align}46\\-36\\ \hline\\ \end{align}$
$\begin{align}75\\-41\\ \hline\\ \end{align}$
$\begin{align}85\\-12\\ \hline\\ \end{align}$
$\begin{align}56\\-45\\ \hline\\ \end{align}$

Answers to Exercise 3

12
32
12
45
11
23
20
62
71
12
41
16
10
34
73
11

Exercise 4

Find the differences. Check your work using the answer key at the end of the exercise.

$\begin{align}476\\-413\\ \hline\\ \end{align}$
$\begin{align}873\\-560\\ \hline\\ \end{align}$
$\begin{align}589\\-384\\ \hline\\ \end{align}$
$\begin{align}793\\-170\\ \hline\\ \end{align}$
$\begin{align}228\\-123\\ \hline\\ \end{align}$
$\begin{align}995\\-452\\ \hline\\ \end{align}$
$\begin{align}869\\-423\\ \hline\\ \end{align}$
$\begin{align}769\\-405\\ \hline\\ \end{align}$
$\begin{align}788\\-435\\ \hline\\ \end{align}$
$\begin{align}579\\-234\\ \hline\\ \end{align}$
$\begin{align}958\\-403\\ \hline\\ \end{align}$
$\begin{align}696\\-251\\ \hline\\ \end{align}$
$\begin{align}657\\-435\\ \hline\\ \end{align}$
$\begin{align}745\\-412\\ \hline\\ \end{align}$
$\begin{align}967\\-143\\ \hline\\ \end{align}$

Answers to Exercise 4

63
313
205
623
105
543
446
364
353
345
555
445
222
333
824

Topic B Self-Test

Mark /27 Aim 23/27

Find the difference. Be sure to check your answers. (6 marks)
1. $\begin{align}16\\-8\\ \hline\\ \end{align}$
2. $\begin{align}18\\-9\\ \hline\\ \end{align}$
3. $\begin{align}14\\-8\\ \hline\\ \end{align}$
4. $\begin{align}11\\-4\\ \hline\\ \end{align}$
5. $\begin{align}9\\-3\\ \hline\\ \end{align}$
6. $\begin{align}17\\-9\\ \hline\\ \end{align}$
Find the difference. Be sure to check your answers. (6 marks)
1. $\begin{align}896\\-422\\ \hline\\ \end{align}$
2. $\begin{align}788\\-531\\ \hline\\ \end{align}$
3. $\begin{align}549\\-318\\ \hline\\ \end{align}$
4. $\begin{align}936\\-702\\ \hline\\ \end{align}$
5. $\begin{align}936\\-725\\ \hline\\ \end{align}$
6. $\begin{align}654\\-242\\ \hline\\ \end{align}$
Solve each of the following word problems. Be sure to include the unit of measure in your answer. Be sure to circle the information and underline what’s being asked.(6 marks, 2 marks each)
1. At noon the temperature was 34 degrees Celsius. At nine o’clock in the evening, it was 12 degrees Celsius. How many degrees did the temperature drop?
2. Misha’s family is on a 179 kilometer trip. They have already gone 123 kilometers. How much farther to they have to go?
3. The Burj Khalifa in Dubai is one of the tallest buildings in the world at 828 metres. The Eiffel Tower in Paris is 324 metres tall. How much taller is the Burj Khalifa than the Eiffel Tower?

Answers to Topic B Self Test

1. 8
2. 9
3. 6
4. 7
5. 6
6. 8
1. 474
2. 257
3. 231
4. 234
5. 211
6. 412
1. 22 degrees Celsius
2. 56 kilometres
3. 504 metres