Mental Math In Multiplication By Nine

Previous Requirement Lessons

• Number Place Value In Mathematics

• Number Place Value

• Basic Number Operation Vocabulary 1

• Vertical Subtraction ( with regrouping ).

Multiplication in mathematics is using the repeated addition. Multiples of 9 are any number you get ( the products ) from multiplying 9 with integer ( whole number ). 

Multiple 1 To 10 With Nine

Question

1 × 9 = ...
2 × 9 = ...
3 × 9 = ...
4 × 9 = ...
5 × 9 = ...
6 × 9 = ...
7 × 9 = ...
8 × 9 = ...
9 × 9 = ...
10 × 9 = ...

First Step

Write 0 at the left of multiplier number.

01 × 9 = ...

Second Step

Write 0 in the result ( at the right side of equal sign notation ) because every number multiple by 0 get zero. This zero number place in the tens number place value.

01 × 9 = 0 ...

Third Step

Multiply the multiplier number with multiplicand number. Write the nine.

01 × 9 = 09

Fourth Step

Write 0 at the left of multiplier number. in the second row result, write a number after  the number from the previous row ( that is 1 ) as tens number place value. Then write a number before the number from the previous row ( that is 8 ) as ones number place value. So the result is eighteen.

01 × 9 = 09

02 × 9 = 18

Fifth Step

Write 0 at the left of multiplier number. in the third row result, write a number after  the number from the previous row ( that is 2 ) as tens number place value. Then write a number before the number from the previous row ( that is 7 ) as ones number place value. So the result is twenty seven.

01 × 9 = 09

02 × 9 = 18

03 × 9 = 27

Next Step

Repeat the fifth step until all question rows is finished.

01 × 9 = 09

02 × 9 = 18

03 × 9 = 27

04 × 9 = 36

05 × 9 = 45

06 × 9 = 54

07 × 9 = 63

08 × 9 = 72

09 × 9 = 81

10 × 9 = 90

Result

Erase each zero in the first digit of multiplier.

1 × 9 = 9

2 × 9 = 18

3 × 9 = 27

4 × 9 = 36

5 × 9 = 45

6 × 9 = 54

7 × 9 = 63

8 × 9 = 72

9 × 9 = 81

10 × 9 = 90

Multiply Every Digit With Nine

Example

27 × 9 = ...

Number factor are:

• Multiplicand number is 27.
• Multiplier number is 9.

The mental math steps:

1. Multiply the number by 10:
   27 × 10 = 270
2. Subtract the result number from previous step by the original number ( multiplicand number ).
   270 - 27 = 243

Bibliography

https://byjus.com/

https://www.ck12.org/

https://www.splashlearn.com/

https://www.vedantu.com/

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Subject Topics Of Math