In this topic, students will:
multiply multiples of 10, 100, and 1,000 using mental math and place-value strategies
use rounding to estimate products, and check if answers are reasonable
use arrays and partial products to multiply 2- and 3-digit numbers by 1-digit numbers
use area models and the Distributive Property to multiply larger numbers
use place value and partial products to multiply 3- and 4-digit numbers by 1-digit numbers
use place value and properties of operations to multiply mentally
choose an appropriate strategy to multiply 2-, 3-, and 4-digit numbers by 1-digit numbers
Vocabulary:
Commutative (order) property of multiplication - numbers can be multiplied in any order and the product will be the same
Distributive property - this property states that a multiplication fact can be broken apart into the sum of two other multiplication facts
Associative property of multiplication - this property states that you can change the grouping of the factors and the product will be the same
Numerical expression - contains numbers and at least one operation
Compensation - choosing numbers close to the numbers in a problem to make computation easier, and then adjusting the answer for the numbers chosen
Partial products - products found by breaking one factor in a multiplication problem into ones, tens, hundreds, and so on and then multiplying each of these by the other factor
Array - an arrangement of objects in equal rows and columns
Area model - a rectangle used to model the multiplication and division of whole numbers
At-home Practice:
Supplies:
a deck of cards (remove face cards)
paper and pencil
Divide the deck evenly between players. Player 1 flips over two cards and multiplies them. Player 1 then makes one of the numbers a multiple of 10. He/she should then multiply the cards using the new number. (ex. Player 1 flips over a 7 and 4. He/she multiples 7 x 4 = 28. He/she then makes the 4 a 40 and multiplies 7 x 40 = 280.) Player 2 repeats the same steps as Player 1. Compare the products (answer). Whoever has the larger product wins all the cards. Continue playing until one player has all of the cards.