Chapter 5 – 2-Digit Subtraction

Essential Question: How do you use place value to subtract 2-digit numbers with and without regrouping?

Grade 2 Common Core State Standards

CC.2.1.2.B.3 Use place-value understanding and properties of operations to add and subtract within 1,000.

CC.2.2.2.A.1Represent and solve problems involving addition and subtraction within 100

CC.2.2.2.A.2 Use mental strategies to add and subtract within 20

Objectives

-The students will break apart a 1-digit subtrahend to subtract it from a 2-digit number.

-The students will break apart a 2-digit subtrahend to subtract it from a 2-digit number.

-The students will model 2-digit subtraction with regrouping.

-The students will draw quick pictures and record 2-digit subtraction using the standard algorithm.

-The students will record 2-digit subtraction using the standard algorithm.

-The students will practice 2-digt subtraction with and without regrouping.

-The students will rewrite horizontal subtraction problems vertically in the standard algorithm format.

-The students will use addition to find differences.

-The students will solve problems involving 2-digit subtraction using the strategy, draw a diagram.

-The students will represent subtraction situations with number sentences using a symbol for the unknown number.

-The student will analyze word problems to determine what operations to use to solve multistep problems.

Vocabulary Terms

Addends- numbers added together in addition problems/ 7 and 2 are the addends in the number sentence 7 + 2 = 9

Column- a vertical arrangement of numbers or items

Difference- the answer to a subtraction problem/3 is the difference in the number sentence 7 – 4 = 3

Digits- the symbols used in a numeration systems; the ten digits used in our base-ten numeration system are 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9

Minuend- number from which another number is to be subtracted/first number in a subtraction number sentence 28 – 7 = 21

Minus sign- a symbol used in a subtraction problem

Ones- the value of a digit in the ones position

Regroup- an action that involves changing a number from one form to an equivalent form

Subtrahend- number you subtract from another number/second number in a subtraction number sentence 28 – 7 = 21

Tens- the value of a digit in the tens position

Helpful Tips

Write 2-digit numbers, such as 56, 67, and 89, each on a separate index card. Use a pencil and a paper clip to make a pointer for the spinner. Have your child choose a card, spin the pointer, and subtract the number on the spinner from the number on the card.