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Decimal Puzzles

Solve Sridharacharya's division problem from the Patiganita with decimals, and place digits to build the biggest and smallest products.

6 micro-lessons

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A Problem from Patiganita

Sridharacharya's division problem, written with decimals.

An old problem (Textbook p. 94, Q6)

Sridharacharya, an Indian mathematician who lived more than a thousand years ago, set this problem in his book Patiganita:

$6\frac{1}{4}$ is divided by $2\frac{1}{2}$ , and $60\frac{1}{4}$ is divided by $3\frac{1}{2}$ . Tell the quotients separately.

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Solving Sridharacharya's Problem

Two quotients, and one hides the magic number 142857.

Problem. Find $6.25 \div 2.5$ and $60.25 \div 3.5$ .

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Mixed Numbers as Decimals

Convert and divide.

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$6\frac{1}{4} = ?$

Building Products on Purpose

Where you place digits decides how big a product is.

Place matters (Textbook p. 94, Q7 and Q10)

In $\square\square.\square$ the first box is tens, the second ones, the third tenths.

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Digits 2, 4, 5, 8, 0

Filling □□.□ × □.□ for the biggest and smallest products.

Problem. Use 2, 4, 5, 8 and 0 once each in $\square\square.\square \times \square.\square$ to get (a) the maximum product, (b) the minimum, (c) a product greater than 150, (d) the product nearest to 100, (e) the product nearest to 5. (Textbook p. 94, Q10; the first box can't be 0)

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Fill the Boxes Two Ways

Find two different ways to make 2.4 and 14.5 as products.

Fill the boxes in at least 2 different ways

Math Talk, Textbook p. 94, Q7. Fill the boxes with decimals or whole numbers, in at least 2 different ways each.

(a) $\square \times \square = 2.4$

(b) $\square \times \square = 14.5$

(a) Two ways to make 2.4*

Check each product.

(b) Two ways to make 14.5*

Check each product.

← previousEveryday Decimals next →Review: Another Peek Beyond The Point

A Problem from Patiganita

Sridharacharya's division problem, written with decimals.

An old problem (Textbook p. 94, Q6)

Sridharacharya, an Indian mathematician who lived more than a thousand years ago, set this problem in his book Patiganita:

$6\frac{1}{4}$ is divided by $2\frac{1}{2}$ , and $60\frac{1}{4}$ is divided by $3\frac{1}{2}$ . Tell the quotients separately.

1 / 2

Solving Sridharacharya's Problem

Two quotients, and one hides the magic number 142857.

Problem. Find $6.25 \div 2.5$ and $60.25 \div 3.5$ .

1 / 5

Mixed Numbers as Decimals

Convert and divide.

1 / 4

$6\frac{1}{4} = ?$

Building Products on Purpose

Where you place digits decides how big a product is.

Place matters (Textbook p. 94, Q7 and Q10)

In $\square\square.\square$ the first box is tens, the second ones, the third tenths.

1 / 3

Digits 2, 4, 5, 8, 0

Filling □□.□ × □.□ for the biggest and smallest products.

1 / 7

Fill the Boxes Two Ways

Find two different ways to make 2.4 and 14.5 as products.

Fill the boxes in at least 2 different ways

Math Talk, Textbook p. 94, Q7. Fill the boxes with decimals or whole numbers, in at least 2 different ways each.

(a) $\square \times \square = 2.4$

(b) $\square \times \square = 14.5$

(a) Two ways to make 2.4*

Check each product.

(b) Two ways to make 14.5*

Check each product.