Merryn's copy of Addition 1

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Question 1

Write the following questions down on paper and evaluate them without using a calculator. You can use any method you wish to practice.

If you click on Show steps you will see full working for the standard method. Click on Try another question like this one to get a new pair of numbers to add.

a)

$\var{b2digit}+\var{b3digit} =$ Expected answer:

Generally, we set up $\var{b2digit}+\var{b3digit}$ with the ones and the tens columns lined up vertically:

	$\var{bdigs[1]}$	$\var{bdigs[0]}$	$+$
$\var{bdigs[4]}$	$\var{bdigs[3]}$	$\var{bdigs[2]}$
	$\phantom{0}$

Now we add the digits in the ones column.

This results in $\var{bunitsum}$ and so we place $\var{bunitsumlastdigit}$ under the line in the ones column and carry the $1$ into the tens column.

	$\overset{\color{red}1}{\var{bdigs[1]}}$	$\overset{\phantom{1}}{\var{bdigs[0]}}$	$+$
$\var{bdigs[4]}$	$\var{bdigs[3]}$	$\var{bdigs[2]}$
		$\color{red}{\var{bUnitSumLastDigit}}$

Now we add the digits in the tens column.

This results in $\var{bTenSum}$ and so we place $\var{bTenSumlastdigit}$ under the line in the tens column and carry the $1$ into the hundreds column.

${\overset{\color{red}1}{\phantom{0}}}$	$\overset{1}{\var{bdigs[1]}}$	$\overset{\phantom{1}}{\var{bdigs[0]}}$	$+$
$\var{bdigs[4]}$	$\var{bdigs[3]}$	$\var{bdigs[2]}$
	$\color{red}{\var{bTenSumlastdigit}}$	${\var{bUnitSumLastDigit}}$

Now we add the digits in the hundreds column.

This is $\var{bsumhun}$ so we place $\var{bsumhun}$ under the line in the hundreds column.

	$\overset{1}{\phantom{0}}$	$\overset{1}{\var{bdigs[1]}}$	$\overset{\phantom{1}}{\var{bdigs[0]}}$	$+$
	$\var{bdigs[4]}$	$\var{bdigs[3]}$	$\var{bdigs[2]}$
$\phantom{\var{bsumhuncarry}}$	$\color{red}{\var{bsumhunlastdigit}}$	$\var{bTenSumlastdigit}$	${\var{bUnitSumLastDigit}}$

The answer is therefore $\var{bans}$ .

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b)

$\var{threedigit1}+\var{threedigit2} =$ Expected answer:

Generally we set up $\var{threedigit1}+\var{threedigit2}$ with the ones, tens and hundreds columns lined up vertically:

$\var{cdigs[2]}$	$\var{cdigs[1]}$	$\var{cdigs[0]}$	$+$
$\var{cdigs[5]}$	$\var{cdigs[4]}$	$\var{cdigs[3]}$
	$\phantom{0}$

Now we add the digits in the ones column.

This results in $\var{cunitsum}$ and so we place $\var{cunitsumlastdigit}$ under the line in the ones column and carry the $1$ into the tens column.

$\overset{\phantom{1}}{\var{cdigs[2]}}$	$\overset{\color{red}1}{\var{cdigs[1]}}$	$\overset{\phantom{1}}{\var{cdigs[0]}}$	$+$
$\var{cdigs[5]}$	$\var{cdigs[4]}$	$\var{cdigs[3]}$
		$\color{red}{\var{cunitSumLastDigit}}$

Now we add the digits in the tens column.

This results in $\var{ctenSum}$ and so we place $\var{ctenSumlastdigit}$ under the line in the tens column and carry the $1$ into the hundreds column.

${\overset{\color{red}1}{\var{cdigs[2]}}}$	$\overset{1}{\var{cdigs[1]}}$	$\overset{\phantom{1}}{\var{cdigs[0]}}$	$+$
$\var{cdigs[5]}$	$\var{cdigs[4]}$	$\var{cdigs[3]}$
	$\color{red}{\var{ctenSumlastdigit}}$	${\var{cunitSumLastDigit}}$

Now we add the digits in the hundreds column.

This is $\var{chunsum}$ so we place $\var{chunsum}$ under the line so that its rightmost digit is in the hundreds column.

	$\overset{1}{\var{cdigs[2]}}$	$\overset{1}{\var{cdigs[1]}}$	$\overset{\phantom{1}}{\var{cdigs[0]}}$	$+$
	$\var{cdigs[5]}$	$\var{cdigs[4]}$	$\var{cdigs[3]}$
$\color{red}{\var{chuncarry}}$	$\color{red}{\var{chunsumlastdigit}}$	$\var{ctenSumlastdigit}$	${\var{cunitSumLastDigit}}$

The answer is therefore $\var{cans}$ .

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Merryn's copy of Addition 1

a)

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