# California - Grade 1 - Math - Numbers and Operations in Base Ten - Mental Math - 1.NBT.5

### Description

Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

• State - California
• Standard ID - 1.NBT.5
• Subjects - Math Common Core

### Keywords

• Math
• Numbers and Operations in Base Ten

## More California Topics

Compose two-dimensional shapes (rectangles, squares, trapezoids, triangles, half-circles, and quarter-circles) or three-dimensional shapes (cubes, right rectangular prisms, right circular cones, and right circular cylinders) to create a composite shape, and compose new shapes from the composite shape.1

Distinguish between defining attributes (e.g., triangles are closed and three-sided) versus non-defining attributes (e.g., color, orientation, overall size) ; build and draw shapes to possess defining attributes.

Partition circles and rectangles into two and four equal shares, describe the shares using the words halves, fourths, and quarters, and use the phrases half of, fourth of, and quarter of. Describe the whole as two of, or four of the shares. Understand for these examples that decomposing into more equal shares creates smaller shares.

Use addition and subtraction within 20 to solve word problems involving situations of adding to, taking from, putting together, taking apart, and comparing, with unknowns in all positions, e.g., by using objects, drawings, and equations with a symbol for the unknown number to represent the problem.

Express the length of an object as a whole number of length units, by laying multiple copies of a shorter object (the length unit) end to end; understand that the length measurement of an object is the number of same-size length units that span it with no gaps or overlaps. Limit to contexts where the object being measured is spanned by a whole number of length units with no gaps or overlaps.

## Here is the skill that California requires you to master

• State Test California Assessment of Student Performance and Progress (CAASPP)
• State Standards California Common Core State Standards
• Subject Math
• Topic Name Mental Math
• Standard ID 1.NBT.5
• Description
Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.

### Education Galaxy’s California Content Standards and California Assessment of Student Performance and Progress (CAASPP)

Education Galaxy’s California Content Standards and California Assessment of Student Performance and Progress (CAASPP) preparation program provides online assessment and practice for students in Grades K-5 to help build mastery towards the California Common Core State Standards. Our unique online program is easy to use and enjoyable for both teachers and students. Students work on their Study Plans practicing important concepts while teachers pull formative assessment reports to identify the strengths and weaknesses of their classroom and individual students.