Florida B.E.S.T. MA.1.AR.2.3

Math1st GradeDevelop an understanding of the relationship between addition and subtraction.

The Standard

Determine the unknown whole number in an addition or subtraction equation, relating three whole numbers, with the unknown in any position.

Florida B.E.S.T. Standards for Mathematics

Teacher's field guide

What Students Need to Do: Students find the number that makes an addition or subtraction equation true. They solve when the missing number appears before, between, or after the other numbers.
What Mastery Looks Like: Students correctly find a missing number at the beginning, middle, or end of an equation. They can use counters, drawings, or inverse operations to explain and check each answer.
Common Misconceptions: Students often treat the blank as the answer and ignore its position. They may read the equal sign as a command to calculate, or add when the missing number is a subtrahend.
How to Assess It: Give an exit ticket with □ + 5 = 12, 14 − □ = 8, and 9 = 3 + □. Ask students to solve each and draw a model for one.

Lesson moves

Use counters and number cards to build equations such as □ + 3 = 8, then change the blank's position and solve again.
Discuss how to solve 9 = □ + 4, then have students explain how subtraction can check the answer.
Partners draw equation cards with blanks in different positions, solve them, and earn a point after checking each answer with an inverse operation.
Set up a pretend fruit stand where students find missing amounts in stories such as 10 apples minus some apples equals 6 apples.

Free download

$Preview of the MA.1.AR.2.3 printable worksheet$

A ready-to-print activity worksheet aligned to MA.1.AR.2.3, with an answer key for the teacher on its own page. No account needed.

PDF, US Letter, prints cleanly in black and white.

Keep exploring

Grade, subject, topic, and the complete standard are prefilled. Create one free, no account needed.