Chapter 4: Multiply by One-Digit Numbers

Vocabulary

100

A number that is multiplied by another number

Factor

200

Rounding factors to their greatest place

Estimate

300

Uses place value to exchange equal amounts when renaming a number 

Regroup

400

Finding the product for the tens and ones separately, then adding them together

Partial Product

500

You can multiply the addends of a number and then add the products

Distributive Property

10, 100, & 1,000/ Estimating

100

90 x 5

450

200

6 x 500

3,000

300

4 x 8,000

32,000

400

Estimate. Round to the greatest place value.

8 x 9,716

8 x 10,000 = 80,000

500

Will the estimate be greater or less than the actual product?

6 x 5,215

Less than because you have to round 5,215 down to 5,000. The actual product will be greater than the estimate which is 30,000.

Multiply!!!!!!

100

13 x 3

    1   3             

x       3

     3  9

200

26 x 3

  ₁

    2   6             _{2 x 3 = 6 + 1 = 7}

x       3

    7   8

300

49 x 8

  ₇

    4   9             _{4 x 8 = 32 + 7 = 39}

x       8

  3  9 2

400

2,006 x 4

  _{4                 2}

    2,    0    0    6              _{0 x 4 = 0 + 2 = 2}

x                     4              

    8,     0    2   4

500

662 x 7

  _{4       1}

    6    6    2              _{6 x 7 = 42 + 1 = 43}

x              7              _{6 x 7 = 42 + 4 = 46}

  4,  6   3   4

Word Problems

100

There are five girls in Dina's scout troop. They are going to an amusement park. Children's tickets cost $22. What is the total cost of admission? Is an estimate or an exact answer needed?

Need exact answer since they want to know the cost of admission and did not say about.

    2   2 

x       4              

    8   8

$88

200

Each motorized scooter at the scooter store costs $75. About how much would 7 motorized scooter cost? Is an estimate or an exact answer needed?

It says about so we can estimate.

75 rounds to 80

80 x 7 = $560

Need about $560

300

Each fourth grade class reads a total of 495 minutes each week. Suppose there are 4 fourth grade classes. How many minutes are read each week?

495 x 4 = x

  _{3       2}

    4    9    5              _{9 x 4 = 36 + 2 = 38}

x              4              _{4 x 4 = 16 + 3 = 19}

  1,  9   8   0

1,980 minutes

400

Each day, Sparky eats three treats. How many does he eat in one year?

1 year = 365 days

   _{1       1}

    3    6    5              _{6 x 3 = 18 + 1 = 19}

x              3              _{3 x 3 = 9 + 1 = 10}

  1,  0   9   5

1,095 treats

500

Each fourth grade class at Tannon Elementary School wants to raise $475 for a local charity. There are 5 fourth grade classes. Rianna says that the overall goal is $2,055. Find and correct her mistake.

Rianna forgot to regroup. The overall goal is $2,375.

She most likely did this:

    4    7    5              _{**Forgot the to bring the tens up**}

x              5              

  2,  0   5   5

This is the right way:

  _{3       2}

    4    7    5              _{7 x 5 = 35 + 2 = 37}

x              5              _{4 x 5 = 20 + 3 = 23}

  2,  3   7   5