# How Benchmarks of 5 and 10 Build Remarkable Number Sense

If you have been with me for any length of time you know that I am all about simple and effective math instruction. Finding opportunities to build number sense by illuminating the benchmarks of 5 and 10 fits the bill on both counts.

#### Students with number sense understand how numbers relate to 5 and 10.

A kindergartner with number sense sees 7 on a ten frame and notices that it is 2 more than 5 and 3 less than 10.

A first-grader with number sense knows that 9 is only 1 away from 10 and uses that to solve problems like 9 + 4.

A second-grader with number sense knows that 80 is 20 away from 100 because 8 tens + 2 tens = 10 tens.

Fast forward…

A fifth-grader with number sense knows that 0.7 + 0.4 is the same as 0.7 + 0.3 + 0.1

#### Tools for Benchmarks of 5 and 10

Benchmarks of 5 and 10 are one of the four number relationships and that means that incorporating opportunities for your students to see, use and relate their learning to these relationships is an incredibly effective way to build number sense.

You can simply incorporate benchmarks of  5 and 10 into your instruction by selecting tools that lend themselves to this relationship.

• A 5 frame of a 10 frame makes this relationship visual for your students. And, yes, because you are using a visual tool you are ALSO boosting spatial relationships and getting more bang for your number sense buck ðŸ™‚
• Using a rekenrek allows your students to see the 5s and 10s embedded in numbers.
• Even some dot pictures or dice patterns will highlight the relationship of numbers to 5 and 10!

#### Number Sense Games for Benchmarks of 5 and 10

• Which Is Closer? Give your students a number. They simply have to determine whether it is closer to 5 or 10. You say “7” and your students respond, “5”! Ask a student to report out “how they know” looking for an answer that states 7 is only 2 away from 5 but is 3 away from 10.
• Differentiate
• Give your students a number path to refer to as they answer the questions if they need visual support when you begin the activity.
• Adjust the numbers in the game depending on your grade level. In 1st grade ask students, for example, whether a number is closer to 20, 25 or 30. In 4th grade ask if a number is closer to 1,000, 1,500 or 2,000. In 5th grade ask if a number is closer to 0, 0.5 or 1.0.
• Spice it Up!
• Turn this activity into an active game by putting the benchmark numbers on index cards on the whiteboard. Break your students up into lines and for each example, have the first person in each line run-up to the board to touch the closest benchmark number. Either keep score and create a competition between the teams or ask both players to return to the line of the winning player for a less competitive, longer playing game.

• Name My Number- Show your students an image of either a ten frame or a rekenrek and ask your students to name the number as quickly as possible.
• Differentiate

• In kindergarten, this may be the full extent of the activity! Using a regular or irregular pattern on a five or ten frame will allow your students to see the numbers they are naming relative to five and ten.
• In second grade, consider filling the ten frame with place value disks. For example, fill the frame with 6 disks each labeled “10” and ask your students what number you have made. How quickly are they able to identify 90? Ask your students how they knew it was 90 so quickly. Did they see 5 tens and 4 tens? Did they see that they were only one ten shy of 100?
• In fourth grade, play using place value disks but also ask your students to consider how place values related. EX: If you know seven “one-thousands” is 7,000 what do you think we would have if I filled the same number of spaces with “ten-thousands”?

Think about your current instruction- is there a way to illuminate the relationship of numbers to 5 and 10? Can you make this relationship visible and tangible for your students? It’s a simple and effective shift you can make to get more bang for your number sense buck during your math instruction

## Looking for easy ways to incorporate number sense into your instruction?

Try these number sense boosters! You and your students will love them. Each activity is based on a skill or standard that is generally taught in 1st or 2nd grade – but with a number sense boosting twist!