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

### Description

Mentally find 10 more or 10 less than a given two-digit number without having to count by ones and explain the reasoning used.

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

### Keywords

• Math
• Numbers and Operations in Base Ten

## More Tennessee Topics Add three whole numbers whose sum is within 20 to solve contextual problems using objects, drawings, and equations with a symbol for the unknown number to represent the problem. Count to 120, starting at any number. Read and write numerals to 120 and represent a number of objects with a written numeral. Count backward from 20. Add a two-digit number to a one-digit number and a two-digit number to a multiple of ten (within 100). Use concrete models, drawings, strategies based on place value, properties of operations, and/or the relationship between addition and subtraction to explain the reasoning used. Subtract multiples of 10 from multiples of 10 in the range 10-90 using concrete models, drawings, strategies based on place value, properties of operations, and/or the relationship between addition and subtraction. Order three objects by length; compare the lengths of two objects indirectly by using a third object.

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

• State Standards Tennessee State Standards
• Subject Math
• Topic Name Mental Math
• Standard ID 1.NBT.5
• Description
Mentally find 10 more or 10 less than a given two-digit number without having to count by ones and explain the reasoning used.  