# Number Sentences - 1 more/1 less, 10 more/10 less

One of the first steps towards advanced math includes the ability to read a (word) sentence and convert it into numbers. Once students learn to count and skip count and understand the concepts of "more" and "less," they can start to solve "more" and "less" number sentences.

Sentences that ask students to find "1 more" or "1 less" put students' counting (and counting backwards) skills to use. **If a student can easily move up and down the number line, he or she should be able to easily complete "1 more" and "1 less" number sentences.** If a student can do "more" sentences and but not "less" sentences, work with the student on counting down (or counting backwards). Many students learn to count backwards simultaneously while learning to count up, but students who struggle with counting down tend to struggle with subtraction, so solving these sentences (and building the backwards counting skills required to solve the sentences) is a good first step towards subtraction.

Next, have students who can count by 10 complete the "10 more" and "10 less" sentences. Completing these sentences just requires students to count up by 10s (starting from random numbers) and count down by 10s (starting from random numbers).

These exercises are very helpful for diagnosing students who struggle with number sense. **Students with good number sense can complete these exercises easily. Students who have to think a lot to solve these problems need to practice counting, skip counting, backwards counting, and understanding the base-10 system. **

#### Practice Problems:

## Number Sentences (1 more/1 less than)

- What is one more than 12?
- What is one more than 29?
- What is one more than 22?
- What is one more than 14?
- What is one more than 30?
- What is 1 more than 10?
- What is 1 less than 27?
- What is 1 less than 36?
- What is 1 less than 25?
- What is 1 less than 50?
- What is 1 less than 9?
- What is 1 less than 21?

## Number Sentences (10 more/10 less than)

- 10 more 20 than ?
- 10 more 15 than?
- 10 more 7 than?
- 10 more 12 than?
- 10 more 5 than?
- 10 more 90 than?
- 10 less 70 than?
- 10 less 30 than?
- 10 less 25 than?
- 10 less 90 than?
- 10 less 55 than?
- 10 less 100 than?

#### Answer Key:

## Number Sentences - 1 more/1 less, 10 more/10 less

- What is 1 more than 2?
- What is 1 more than 9?
- What is 1 more than 17?
- What is 10 more than 2?
- What is 10 more than 24?
- What is 10 more than 79?
- What is 1 less than 3?
- What is 1 less than 8?
- What is 1 less than 16?
- What is 10 less than 15?
- What is 10 less than 31?
- What is 10 less than 56?