Subtraction Strategies and Concepts

The video tutorial covers mental subtraction techniques, focusing on decomposing numbers and using compensation strategies. It provides examples, such as calculating temperature drops and subtracting numbers ending in 9 or 99. The tutorial also explains subtraction rules, including subtracting from zero, and offers practice problems to reinforce learning.

What is the first step in mentally subtracting numbers?

• Multiply the numbers

• Break up the smaller number into parts

• Divide the numbers

• Add the numbers together

What is the term used when breaking numbers into parts for subtraction?

• Dividing

• Composing

• Decomposing

• Multiplying

In the temperature drop example, what was the initial temperature?

• 69 degrees

• 60 degrees

• 86 degrees

• 70 degrees

How can 17 be decomposed for subtraction?

• 10 and 7

• 8 and 9

• 15 and 2

• 20 and -3

What is the result of subtracting a number from itself?

• Zero

• The number itself

• Negative one

• One

What happens when you subtract zero from a number?

• The number decreases by one

• The number remains the same

• The number becomes zero

• The number doubles

What strategy is used for numbers ending in 9 or 99?

• Multiplication

• Compensation

• Decomposition

• Division

How do you adjust the number 99 using the compensation strategy?

• Divide by 2 to make it 49.5

• Add 1 to make it 100

• Multiply by 2 to make it 198

• Subtract 1 to make it 98

What is the result of 223 minus 199 using compensation?

• 99

• 223

• 124

• 24

What is the result of 34 minus 18 using decomposition?

• 16

• 18

• 20

• 14