# Addition and Subtraction Whole Number Calculation Algorithmic Scoring Guide

1
• Counts on for values to 20
• Uses five and ten as anchors

2
• Can tell one more and one less.
• Can tell two more and two less.
• Compose and decompose numbers to 20
• Mentally Adds and subtracts values to 20

3
• Add and subtract from left to right by decomposing double digit numbers to tens and ones.
• Working with the tens, then working with the ones, and then adding the tens and ones.

4
• Adds on or subtracts from a two digit numer
• Mentally Adds and subtracts values to 100 including regrouping for addition and subtraction
• Adds and subtracts money values by composing and decomposing into coin values.

5
• Constructs and deconstructs addition and subtraction problems to 10 000.
• Regroup with addition fairly easily
• Regrouping with subtraction is cumbersome with problems requiring multiple regroupings

6
• Constructs and deconstructs addition and subtraction problems of any size with and without regrouping until confidence in the accuracy of the solution is attained.