Key Concepts
- Multiplication through partial products
- Multiplication through estimation
Use partial products to multiply by 2-digit numbers
What is meant by partial products?
A product obtained by multiplying a multiplicand by one digit of a multiplier having more than one digit.
Example:
Find the product of 39 x 15.

4. 6.1 Multiplication through estimation and partial products.
Jason donated 16 duffle bags of first aid kits to the American red cross. Each bag contains 12 first aid kits. How many first aid kits did the red cross receive in all?

Find 12 x 16.
Solution:
Draw model for given multiplication.

Estimate: 12 x 16 is about 10 x 15 =150
Step1: First, multiply the ones


Step2: Multiply the tens.


Example2:
Ria distributed 27 fruits per one person in an old age home. There are 16 people in an old age home. How many fruits Ria distributed to all?

Find : 27 x 16.
Solution:
Draw area model for 27 x 16.

Estimate: 16 x 27 is about 15 x 30 = 450
Step1: First, multiply the ones.
20 7


Step2: Multiply the tens. Add the partial products.


Ria distributed 452 fruits.
Example3:
If there are 23 pages in one drawing book. How many pages are there in 12 drawing books?

Find 23 x 12.
Solution:
Estimate: 23 x 12 is about 20 x 10 = 200.
Step1: Multiply 23 x 12.

Step2: Add the partial partial products for the final product.

12 drawing books has 276 pages.
Exercise:
- Estimate the product of 89 X 36.
- Estimate the product of 92 X 78.
- Find all the partial products. Then add to find the final product draw area model as needed.
- 24 x 45
- 37 x 68
- 38 x 56
- Draw area model for the following:
- 23 x 64
- 67 x 89
- 29 x 57
- Find the product of 45 x 30 using partial product model.
- Estimate, find all the partial products. Then add the final product, draw an area model as needed.
- 96 x 23
- 36 x 24
- 56 x 78
- Estimate and find the product of 37 x 23 using partial product model.

- Find the product of 26 x 17. Use partial product model.

- A cultivator sells 56 packets of oyster mushroom. If each packet contains 22 mushrooms. How many mushrooms did the cultivator sell in all?
- If one box contains 45 jelly beans. How many jelly beans do 38 boxes contain?
Concept map:

What have we learned:
- Understand partial product and estimation.
- Identify partial products.
- Understand how to do multiplication through partial products.
- Understand adding partial products.
- Identify estimation for the given numbers.
- Understand how to do multiplication through estimation.
Related topics
Obtuse Angle: Definition, Degree Measure, and Examples
What is an Obtuse Angle? In geometry, an angle that is greater than 90 degrees but lesser than 180 degrees is called an obtuse angle. We can easily recognize an obtuse angle because it extends past a right angle. Obtuse angle explained in detail with examples but first learn about angles. Type of Angles Geometry […]
Read More >>Line Segment in Geometry: Definition, Symbol, Formula, and Examples
A line is a straight, one-dimensional figure that extends endlessly in both directions in geometry. It has no starting and ending points. When we define a starting point but not an ending point of a line, it is called a ray. Another important term associated with the line is a line segment. Line Segment Definition […]
Read More >>Area of Irregular Shapes for Grade 3 – Simple Methods & Examples
What Is the Area of an Irregular Shape? The area of an irregular shape is the space that it occupies, although it does not follow a clean formula. In contrast to the squares or perfect rectangles, irregular shapes have sides that are uneven or their angles don’t line up evenly. That is what makes them […]
Read More >>Addition and Multiplication Using Counters & Bar-Diagrams
Introduction: We can find the solution to the word problem by solving it. Here, in this topic, we can use 3 methods to find the solution. 1. Add using counters 2. Use factors to get the product 3. Write equations to find the unknown. Addition Equation: 8+8+8 =? Multiplication equation: 3×8=? Example 1: Andrew has […]
Read More >>Other topics






Comments: