Second Grade Mathematics
Unit 1

Operational Fluency of Addition and Subtraction

Printable Parent Letter

During Unit 1, your child will work on becoming fluent with adding and subtracting within 20. Basic facts for addition refer to all sums of two one-digit numbers. Over time, fluency with number relationships leads to memory of the addition facts and application to subtraction.  Fluency is defined as solving facts quickly and accurately without halting, stumbling or reversing oneself. 

Students need to:

  • Fluently add and subtract within 20 using mental strategies. By end of Grade 2, know from memory all sums of two one-digit numbers.
  • Use addition and subtraction within (20) to solve one- and two-step word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using drawings and equations with a symbol for the unknown number to represent the problem.
  • Draw a picture graph and a bar graph (with single-unit scale) to represent a data set with up to four categories. Solve simple put-together, take-apart, and compare problems using information presented in a bar graph.
  • Represent whole numbers as lengths from 0 on a number line diagram with equally spaced points corresponding to the numbers 0, 1, 2, ...

Carroll County Public Schools Video Support

Heim Double Ten Frame
Using Double Tens Frames to Add

Patrick Using Organizers
Using an Organizer to Solve Word Problems

Heim Bar Model Comp
Bar Model Word Problem Comparisons


Ways Parents Can Help

  • Keep a set of flash cards in the car to practice as you run errands. Encourage your child to explain the strategy that they used to solve the problem.
  • With a deck of cards, use the number cards to play Fact War. Each player flips 1 card and the player to say the sum first, gets both cards
  • Have your child sort a set of flashcards based on the strategy that they would use to solve the problem. Have them select one strategy pile to solve.
  • Students often overuse "counting on" for all math facts. Help your child to generate facts that are efficient for counting on and facts that are not efficient for counting on (you could create a list or use flashcards to make groups). Encourage your child to explain why counting on would not be efficient for a fact (such as 5+7).

Some Support Sites:
Math in English Basic Fact Crossword Puzzles




Key Vocabulary to Know

Add: to join two or more quantities to get one sum

Addend: any number used to get a sum

Data: collection of information

Difference: difference between two numbers (subtraction)

Equal: having the same amount or value

Equality: state of being equal

Equation: mathematical statement containing an equals sign to show that two expressions are equal

Fluent: solving facts quickly and accurately without halting, stumbling or reversing oneself

Fewer: less than

Graph drawing or diagram used to record information

Inverse Operation: opposite or reverse operations (e.g. addition and subtraction)

Minuend: the quantity that you are subtracting from in a subtraction equation

Minus: to subtract

More: greater than

Number Line: line marked with numbers used to show operations

Number Sentence: mathematical sentence written in numerals and mathematical symbols

Plus: to add

Related Fact: addition and/or subtraction sentences that are alike

Scale: the increment used on a graph

Strategy: a plan, a method or a way to solve a problem

Subtract: to take one quantity away from another

Subtrahend: the quantity subtracted from the minuend in a subtraction equation

Sum: the total or whole amount; the result of adding