In this Grade 4 Eureka Math lesson, students use place value disks on a place value chart to model two-digit by one-digit multiplication, such as 2 × 23 and 4 × 34, while recording partial products vertically. Students practice regrouping ones into tens as they work through multiplication expressions and connect the visual disk model to the standard written method. The lesson builds on prior work with multiples of 10 and mental multiplication strategies from earlier in Chapter 11.
Section 1
Multiply and Regroup with Place Value Disks
To multiply a two-digit number by a one-digit number, calculate the partial products by multiplying the ones and tens places separately.
If a place has 10 or more units, regroup them.
The total product is the sum of the values in each place after regrouping.
Section 2
Connecting Place Value Disks to Partial Products
The partial products algorithm is a written method to record the multiplication shown on a place value chart.
The value of the disks in each place value column corresponds to a partial product in the algorithm.
Expand to review the lesson summary and core properties.
Section 1
Multiply and Regroup with Place Value Disks
To multiply a two-digit number by a one-digit number, calculate the partial products by multiplying the ones and tens places separately.
If a place has 10 or more units, regroup them.
The total product is the sum of the values in each place after regrouping.
Section 2
Connecting Place Value Disks to Partial Products
The partial products algorithm is a written method to record the multiplication shown on a place value chart.
The value of the disks in each place value column corresponds to a partial product in the algorithm.