1.5.C

Math1st Grade

The Standard

use relationships to determine the number that is 10 more and 10 less than a given number up to 120

Texas Essential Knowledge and Skills for Mathematics

Teacher's field guide

What This Standard Means

What Students Need to Do

Students find the number that is 10 greater or 10 smaller than a given number. They use place-value patterns rather than counting one by one.

What Mastery Looks Like

Given a number such as 64, students quickly name 74 and 54. They keep the ones digit the same and handle changes across 100 correctly.

Common Misconceptions

Students may add or subtract 1 instead of 10. They may change the ones digit instead of the tens digit. Crossing 100 can cause errors, such as naming 103 instead of 113 for 10 more than 103.

How to Assess It

Exit ticket: For 46 and 103, write the number that is 10 more and the number that is 10 less. Explain what changed.

Lesson moves

Ways to Teach It

  1. Build a number with base-ten blocks, then add or remove one ten rod and record the new number.

  2. Ask, “What stays the same and what changes when you find 10 more or 10 less?”

  3. Play a number-card game where partners draw a card and race to write 10 more and 10 less.

  4. Use a classroom library count, then ask how many books there would be after adding or removing 10 books.

Keep exploring

Related Standards

Turn this exact standard into a lesson

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