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India
Class VII

Long division - dividing 4 digit numbers

Lesson

Long division with large numbers

If we have a large number, in the thousands, it can seem daunting to solve a division problem. Remember though, we use exactly the same process that we use for smaller numbers. When it comes to long division, it can mean more steps, because we need to work through each of the thousands, hundreds, tens and units. Be sure to allow lots of room for working your problem out down the page, otherwise, it's just like dividing 1 or 2 digit numbers, or dividing 3 digit numbers.

 

Dividing by a 1 digit number

We've seen earlier that when we divide by a 1 digit number, we might end up with some remainder. To express this in decimal format, we always think of our remainder divided by the divisor. For example, we can write a number such as $\frac{5}{10}$510, which we can then express as a decimal, $0.5$0.5.

In Video 1, we divide a 4 digit number by a 1 digit number, and express our remainder as a decimal.

 

Dividing by a 2 digit number

Once you have solved long division of single digit numbers, you can use the same process to divide 2 digit numbers. Let's start thinking why estimating is important.

 

Solving using long division

Now that we are ready to solve the problem using long division, you will see that there is a bit of a surprise lurking in this example! We could have easily have forgotten about the units place, and come out with a very different answer! This time, we don't think about having a remainder, instead we continue on with long division, once we can't share the units. How do we do that? No tricks, just the same process, renaming units to tenths, until there is no more to share.

Remember!

By thinking of the place value of the digits you are working with, you are less likely to make a mistake in your calculations. Your estimate is also a great way to check that your digits are in the correct place value.

 

Worked Examples


QUESTION 1

We want to find $8121\div6$8121÷​6.

  1. Choose the most reasonable estimate for $8121\div6$8121÷​6.

    $1350$1350

    A

    $1454$1454

    B

    $1250$1250

    C

    $14$14

    D
  2. Fill in the multiplication table for $6$6.

    $2$2 $12$12
    $3$3 $18$18
    $4$4 $\editable{}$
    $5$5 $\editable{}$
    $6$6 $\editable{}$
    $7$7 $42$42
    $8$8 $\editable{}$
    $9$9 $\editable{}$
  3. Complete the long division to find $8121\div6$8121÷​6.

      $\editable{}$ $\editable{}$ $\editable{}$ $\editable{}$ $.$. $\editable{}$
    $6$6   $8$8 $1$1 $2$2 $1$1 $.$. $0$0
      $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$   $\editable{}$
      $\editable{}$   $\editable{}$
      $\editable{}$

QUESTION 2

We want to find $7020\div8$7020÷​8.

  1. Choose the most reasonable estimate for $7020\div8$7020÷​8.

    $875$875

    A

    $978$978

    B

    $9$9

    C

    $8700$8700

    D
  2. Fill in the multiplication table for $8$8.

    $2$2 $16$16
    $3$3 $24$24
    $4$4 $\editable{}$
    $5$5 $\editable{}$
    $6$6 $\editable{}$
    $7$7 $56$56
    $8$8 $\editable{}$
    $9$9 $\editable{}$
  3. Complete the long division to find $7020\div8$7020÷​8.

        $\editable{}$ $\editable{}$ $\editable{}$ $.$. $\editable{}$
    $8$8   $7$7 $0$0 $2$2 $0$0 $.$. $0$0
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$   $\editable{}$
      $\editable{}$   $\editable{}$
      $\editable{}$

QUESTION 3

We want to find $5580\div24$5580÷​24.

  1. Choose the most reasonable estimate for $5580\div24$5580÷​24.

    $333$333

    A

    $233$233

    B

    $2$2

    C

    $150$150

    D
  2. Fill in the multiplication table for $24$24.

    $2$2 $48$48
    $3$3 $72$72
    $4$4 $\editable{}$
    $5$5 $\editable{}$
    $6$6 $\editable{}$
    $7$7 $168$168
    $8$8 $\editable{}$
    $9$9 $\editable{}$
  3. Complete the long division to find $5580\div24$5580÷​24.

        $\editable{}$ $\editable{}$ $\editable{}$ $.$. $\editable{}$
    $24$24   $5$5 $5$5 $8$8 $0$0 $.$. $0$0
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$  
      $\editable{}$ $\editable{}$   $\editable{}$
      $\editable{}$ $\editable{}$   $\editable{}$
      $\editable{}$

Outcomes

7.NS.FRN.10

Multiplication and division of decimal fractions

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