PRACTICE: Addition and subtraction

Use the vertical algorithm method.

Write it in a vertical algorithm.\begin{array}{c} & &1 &5 &0 \\ &+ &2 &5 &0 \\ \hline & \\ \hline \end{array}

Add the ones column first.\begin{array}{c} & &1 &5 &0 \\ &+ &2 &5 &0 \\ \hline & & & &0 \\ \end{array}

Add the tens column. 5 + 5 = 10 . Bring down the 0 and carry the 1 to the hundreds column.\begin{array}{c} & &\text{ }^1 1 &5 &0 \\ &+ &2 &5 &0 \\ \hline & & &0 &0 \\ \end{array}

Add the hundreds column.\begin{array}{c} & &\text{ }^1 1 &5 &0 \\ &+ &2 &5 &0 \\ \hline & &4 &0 &0 \\ \end{array}

So 150 + 250 = 400 .

Use the vertical algorithm method.

Write it in a vertical algorithm.\begin{array}{c} & &6 &7 &5 &4 \\ &- & &9 &3 &9 \\ \hline & \\ \hline \end{array}

Subtract the ones column first. In the ones column we can see that 4 is less than 9, so we need to trade 1 ten from the tens place.

So we get 14-9=5 in the ones column and 5 tens becomes 4 tens in the first row.\begin{array}{c} & &6 &7 &4 &\text{ }^1 4 \\ &- & &9 &3 &9 \\ \hline & & & & &5 \\ \hline \end{array}

So for the tens column we have 4 - 3 = 1:\begin{array}{c} & &6 &7 &4 &\text{ }^1 4 \\ &- & &9 &3 &9 \\ \hline & & & &1 &5 \\ \hline \end{array}

In the hundreds column, we can see that 7 is less than 9, so we need to trade 1 thousand from the thousands place.

So we get 17-9=8 in the hundreds column and 6 thousands becomes 5 thousands in the first row.\begin{array}{c} & &5 &\text{ }^1 7 &4 &\text{ }^1 4 \\ &- & &9 &3 &9 \\ \hline & & &8 &1 &5 \\ \hline \end{array}

And for the thousands place we just bring down the 5:\begin{array}{c} & &5 &\text{ }^1 7 &4 &\text{ }^1 4 \\ &- & &9 &3 &9 \\ \hline & &5 &8 &1 &5 \\ \hline \end{array}

So 6754 - 939 = 5815.

Use the vertical algorithm method.

Write it in a vertical algorithm.\begin{array}{c} & & &7 &2 &1 &5 \\ &+ & &7 &0 &3 &9 \\ \hline & \\ \hline \end{array}

Add the ones column first. 5 + 9 =14. Bring down the 4 and carry the 1 to the tens column.

\begin{array}{c} & & &7 &2 &1 \text{ }^1 &5 \\ &+ & &7 &0 &3 &9 \\ \hline & & & & & &4 \\ \hline \end{array}

Then add the tens column, 1 + 1 + 3 = 5:\begin{array}{c} & & &7 &2 &1 \text{ }^1 &5 \\ &+ & &7 &0 &3 &9 \\ \hline & & & & &5 &4 \\ \hline \end{array}

Then add the hundreds column, 2 + 0 = 2:\begin{array}{c} & & &7 &2 &1 \text{ }^1 &5 \\ &+ & &7 &0 &3 &9 \\ \hline & & & &2 &5 &4 \\ \hline \end{array}

Then add the thousands column, 7 + 7 =14. Bring down the 4 and carry the 1 to the ten thousands column.

\begin{array}{c} & &\text{ }^1 &7 &2 &1 \text{ }^1 &5 \\ &+ & &7 &0 &3 &9 \\ \hline & & &4 &2 &5 &4 \\ \hline \end{array}

Then add the ten thousands column, 1 + 0 = 1:\begin{array}{c} & &\text{ }^1 &7 &2 &1 \text{ }^1 &5 \\ &+ & &7 &0 &3 &9 \\ \hline & &1 &4 &2 &5 &4 \\ \hline \end{array}

So 7215 + 7039 = 14\,254 .