Multi-Digit Multiplication
Evaluate the following multiplication problem:
25 x 4 =
100
Evaluate the following multiplication problem:
12 x 70 =
840
4 x 6 = 24, so
40 x 6 =?
240
The numbers on which we operate can be moved or swapped from their position without making any difference to the answer. We will arrive at the same sum (addition) or product (multiplication)
Communtative property
Subtract:
3021 - 2132 =
889
Evaluate the following multiplication problem:
158 x 2 =
316
Evaluate the following multiplication problem:
70 x 14 =
980
7 x 9 = 63, so
700 x 9 = ?
6,300
The pairs of numbers that are first added or multiplied do not matter the results will be the same.
Associative Property
ADD
123 + 456 + 789 =
1,368
Evaluate the following multiplication problem:
351 x 5 =
1755
Evaluate the following multiplication problem:
45 x 76 =
3,420
4 x 5 = 20, so
4 x 500 = ?
2,000
(NOT 200!)
The word that describes the answer to an addition problem.
SUM
What comes next in this pattern?
1,5,9,13....
17
(Add four)
Evaluate the following multiplication problem:
708 x 8 =
5,664
Evaluate the following multiplication problem
92 x 20
1840
6 x 8 = 48, so
60 x 80 = ?
4,800
This can help us determine the product of two number s in a different way
distributive property
Name TWO of the properties of MULTIPLICATION
-Commutative, Distributive, Associative, Identity, etc.
Evaluate the following multiplication problem:
476 x 9 =
4,284
Evaluate the following multiplication problem:
56 x 52
2,912
1 x 1 = 1, so
1000 x 1000 = ?
1,000,000
aka 1 million
When multiplying an amount by 1 or dividing an amount by 1 the answer stays the same.
Identity principle
MENTAL MATH! (Must do it in your head, no writing!)
223 x 4 =
200 x 4 = 800
20 x 4 = 80
3 x 4 = 12
Answer: 892