Question

In a school library, $2721$ books are there. On students request, $9,800$ more books were bought. How many books are there in all.

Answer 1

Step 1: Add the ones

Given: In a school library, $2721$ books are there. On students request, $9,800$ more books were bought.

So, total books in library $=2721+9800$

Sum: $\mathrm{Th}\mathrm{H}\mathrm{T}\mathrm{O}2721+9800$

First add ones $0+0+0=0$,

Write $0$ under ones column.

Step 2: Add the tens

Next add tens $2+0=2$,

Write $2$ under tens column.

Step 3: Add the hundreds

Next add hundreds $7+8=15$,

Write $5$ under hundreds column and carry $1$ to thousands column.

Step 4: Add the thousands

And finally add thousand $1+2+9=12$ (Extra $1$ is carry from hundreds)

Write $12$ under thousand column.

So we get,

$\mathrm{Th}\mathrm{H}\mathrm{T}\mathrm{O}\mathrm{carry}-\mathrm{over}12721+980012521$

Hence, Total numbers of books are $12,521$.