Doubling
How could you use doubling to solve 2 x 4?
1x4 + 1x4 or 2x2 + 2x2
What is 250 - 125?
125
Solve the problem:
A cafeteria has 6 tables with 4 students at each table and 8 extra students sitting at another table.
How many students are in the cafeteria?
32
4 + 5 x 2 = ?
14
Solve: (5+5) x 2 = ?
20
How could you use doubling to solve 6x3?
3x3 + 3x3
What is 270 = 350 - ?
80
Read the question and make a number model to represent the equation:
Ms. Carter’s class has 8 tables with 4 students at each table and a table with 6 students.
(8 x 4) + 6 ?
? = 6 x 1 + 4
10
Solve: 6 x (3+5) = ?
48
How could you use doubling to solve 8x9?
4x9 + 4x9
What is 460 - 265?
195
Solve the problem:
Ms. Rivera’s class has 4 tables with 5 students at each table and 1 table with 2 students.
How many students are in Ms. Rivera’s class?
22
10
Solve: (2+5) x ? = 21
3
How could you use doubling to solve 10 x 12?
10x6 + 10x6 or 5x12 + 5x12
What is 643 - 512?
131
Read the question and make a number model to represent the equation:
At a school assembly, there are 9 rows with 5 students in each row and 7 extra students sitting on the side.
(9 x 5) + 7 = ?
(9 + 1) x 4 + 6 = ?
46
Solve: (3x6) + 9 = ?
27
How could you use doubling to solve 20 x 7?
10x7 + 10x7
What is 887 - 319?
568
Solve the problem:
At a school event, there are 5 rows of chairs with 6 students in each row. There are also 3 smaller groups with 4 students in each group, and 2 extra students standing.
How many students are at the event?
44
? = 3 x (5 + 4) - 15
12
Solve: (5+?) x 4 = 36
9