In order to subtract these two numbers, we will first need to take out a common factor of negative one.

\(\displaystyle 686-981 =-(-686+981) =-(981-686)\)

We can then subtract the terms.

Borrow a one from the tens digit to subtract the ones digits.  The tens digit of 981 becomes a 7.

\(\displaystyle 11-6=5\)

Borrow a one from the hundreds place to subtract the tens digits.  The hundreds place of 981 becomes an eight.

Subtract the tens digits.

\(\displaystyle 17-8 =9\)

Subtract the hundreds digits.

\(\displaystyle 8-6=2\)

The expression becomes:  \(\displaystyle -(295)\)

The answer is:  \(\displaystyle -295\)

Add the ones digits.

\(\displaystyle 4+9+3 = 16\)

Add the tens digits with the carryover.

\(\displaystyle 9+4+1+(1) = 15\)

Add the hundreds digits with the carryover.

\(\displaystyle 8+5+8+(1) = 22\)

Combine the digits together to determine the answer.

The answer is:  \(\displaystyle 2256\)

Add the ones digits.

\(\displaystyle 4+9=13\)

Add the tens digits with the carryover from 13, which is 1.

\(\displaystyle 4+4+(1)=9\)

Add the hundreds digits.  There is no carryover.

\(\displaystyle 9+4=13\)

Add the thousands places with the carryover.

\(\displaystyle 1+2+(1) =4\)

Combine all digits.

The answer is:  \(\displaystyle 4393\)

Add the ones digits.

\(\displaystyle 3+9+7 = 19\)

Add the tens digits with the carryover, which is the tens place of this number.

\(\displaystyle 7+6+4+(1) = 18\)

Add the hundreds places with the carryover.

\(\displaystyle 9+0+8+(1) = 18\)

Add the thousands digits.  If there are no thousands digit for a number, assume it's zero.

\(\displaystyle 0+1+0+(1)=2\)

Combine all the numbers.

The answer is:  \(\displaystyle 2889\)

Add the ones digits.

\(\displaystyle 6+4+7 = 17\)

The carryover is the tens digit of this number.

Add the tens digits with the carryover.

\(\displaystyle 1+8+1+(1) = 11\)

Add the hundreds digits with the new carryover.

\(\displaystyle 2+9+7+(1) = 19\)

The answer is:  \(\displaystyle 1917\)

In order to solve, we can rearrange the numbers so that we are adding the two hundreds digit numbers.

\(\displaystyle 947+687-1098\)

Add the first two terms.

\(\displaystyle 947+687\)

Add the ones digits.

\(\displaystyle 7+7=14\)

Add the tens digits with the carryover.

\(\displaystyle 4+8+(1) = 13\)

Add the hundreds digits with the carryover.

\(\displaystyle 9+6+(1)=16\)

The sum for the first two terms is:  \(\displaystyle 1634\)

Subtract this term with the third term.

\(\displaystyle 1634-1098\)

Borrow a one from the 3 of 1634 to subtract the ones digits.  The tens place becomes a 2.

\(\displaystyle 14-8 = 6\)

Borrow a one from the 6 of 1634 to subtract the tens digits.  The hundreds place becomes a 5.

\(\displaystyle 12-9 =3\)

There is no need to borrow a one from the thousands place to subtract the hundreds digits.

\(\displaystyle 5-0 =5\)

Subtract the thousands places.

\(\displaystyle 1-1=0\)

Combine the numbers.

The answer is:  \(\displaystyle 536\)

Add the ones digits.

\(\displaystyle 7+2=9\)

Add the tens digits.

\(\displaystyle 9+8 = 17\)

Add the hundreds digits with the carryover from the previous calculation, 1.

\(\displaystyle 3+9+(1)=13\)

Repeat the process for the thousands digits.  The thousands digit of 982 is zero.

\(\displaystyle 1+0+(1) =2\)

Combine the ones digits from each calculation.

The answer is:  \(\displaystyle 2379\)

Add the ones digits.

\(\displaystyle 4+1=5\)

Add the tens digits.

\(\displaystyle 7+8=15\)

Add the hundreds digits with the carryover, 1.

\(\displaystyle 8+9+(1) = 18\)

Add the thousands digits with the carryover.

\(\displaystyle 9+0+(1) = 10\)

The answer is:  \(\displaystyle 10855\)

Subtract the ones digits.

\(\displaystyle 8-6=2\)

Borrow a one from the hundreds digits in order to subtract the tens digits.  The hundreds digit of 418 becomes a zero.

Subtract the tens digits.  

\(\displaystyle 11-5 = 6\)

The answer is:  \(\displaystyle 62\)

Add the ones digits.

\(\displaystyle 8+3 =11\)

The carryover is the tens digit.

Add the tens places with the carryover.

\(\displaystyle 5+1+1 =7\)

There is no carryover.  Add the hundreds digits.

\(\displaystyle 9+4 = 13\)

The answer is:  \(\displaystyle 1371\)