Finding Missing Factors in Equations

This lesson teaches how to find a missing factor when the known factor is 7. It introduces two main strategies: using the sum of the digits in the product and dividing even products by 2. The lesson also covers special cases, such as products ending in 5, and emphasizes practice to remember certain facts. The goal is to equip students with techniques to identify missing factors in multiplication problems involving 7.

What is the missing factor in the equation 7 times what number equals 21?

• 5

• 2

• 3

• 4

What is the strategy used to find the missing factor when the product is 21?

• Multiplying digits

• Dividing digits

• Adding digits

• Subtracting digits

If the product is 42, what is the missing factor when using the sum of digits strategy?

• 6

• 5

• 8

• 7

What is the missing factor in the equation 7 times what number equals 63?

• 10

• 7

• 8

• 9

What is the missing factor in the equation 7 times what number equals 42?

• 8

• 7

• 5

• 6

For which sums of digits does the sum of digits strategy work?

• 4, 8, 10

• 1, 5, 7

• 3, 6, 9

• 2, 4, 6

What is the first step in finding the missing factor when the product is an even number?

• Add 5

• Subtract 1

• Divide by 2

• Multiply by 3

What is the missing factor in the equation 7 times what number equals 14?

• 3

• 2

• 1

• 4

How many times do you divide by 2 to find the missing factor in the product 56?

• 1

• 4

• 2

• 3

What is the missing factor in the equation 7 times what number equals 28?

• 2

• 3

• 4

• 5