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SHORT METHODS.

Multiplication and Division.

Art. 1. To multiply a number by 50: Multiply of the

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(a) Find the sum of the fifteen products.

Art. 2. To multiply a number by 51: Take 50 times the

number, to which add the number itself.

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Why? 2400 + 48

= 2448

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(b) Find the sum of the fifteen products.

Art. 3. To multiply a number by 52: Take 50 times the

number, to which add twice the number.

Why?

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(c) Find the sum of the twelve products.

Art. 4. To multiply a number by 49: Take 50 times the number, from which subtract the number itself.

Why?

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Why?

36 × 331

(d) Find the sum of the nine products.

Art. 5. To multiply a number by 331: Multiply of the

number by 100.

of 36 x 100 = 1200

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Art. 6. To multiply a number by 341: the number, to which add the number itself.

331 times 24 = 800
33 times 25 8331

Take 331⁄2 times

Why?

800 + 24 = 824 8331+25=8581

24 × 341 25 × 341

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(f) Find the sum of the twelve products.

Art. 7. To multiply a number by 351: the number, to which add twice the number.

Take 331 times

Why?

=

24 × 351

33

times 24 = 800

800

+48 848

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(g) Find the sum of the nine products.

Art. 8. To multiply a number by 32: Take 33 times the number, from which subtract the number itself. Why?

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Art. 9. To multiply a number by 25: Multiply of the

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(i) Find the sum of the twelve products.

Art. 10. To multiply a number by 26: Take 25 times the number, to which add the number itself. Why?

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Art. 11. To multiply a number by 27: Take 25 times the number, to which add twice the number. Why?

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Art. 12. To multiply a number by 24: Take 25 times

the number, from which subtract the number itself.

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Why?

€768

792

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(1) Find the sum of the twelve products.

Art. 13. To multiply a number by 20: Multiply

of the

number by 100. How may a number be multiplied by 21?

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(m) Find the sum of the nine products.

Art. 14. To multiply a number by 16: Multiply of the number by 100. How may a number be multiplied by

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