# Number Sense Worksheets

Welcome to the number sense page at Math-Drills.com where we've got your number! This page includes Number Worksheets such as counting charts, representing, comparing and ordering numbers worksheets, and worksheets on expanded form, written numbers, scientific numbers, Roman numerals, factors, exponents, and binary numbers. There are literally hundreds of number worksheets meant to help students develop their understanding of numeration and number sense.

In the first few sections, there are some general use printables that can be used in a variety of situations. Hundred charts, for example, can be used for counting, but they can just as easily be used for learning decimal hundredths. Rounding worksheets help students learn this important skill that is especially useful in estimation.

Comparing and ordering numbers worksheets help students further understand place value and the ordinality of numbers. Continuing down the page are a number of worksheets on number forms: written, expanded, standard, scientific, and Roman numerals. Near the end of the page are a few worksheets for older students on factors, factoring, exponents and roots and binary numbers.

## Hundred Charts

Hundred charts are useful not only for learning counting but for many other purposes in math. For example, a hundred chart can be used to model fractions and to convert fractions into decimals. Modeling 1/4 on a hundred chart would require coloring every fourth square. After coloring every fourth square, there would be 25 squares colored in which is 25/100 or 0.25. Not magic, just math. Hundred charts can also be used as graph paper for graphing, learning long multiplication and division or any other purpose. A common use for hundred charts in older grades is to use it to find prime and composite numbers using Eratosthenes Sieve.

## 120 Charts

In the U.S., the Common Core requires students in first grade to learn numbers to 120, so we've included similar charts to the 100's charts above, but extended to 120.

Below are backward versions of the 120 charts.

## Ninety-Nine Charts

One of the issues with 100 charts is that they don't include 0! Below is a request from one of our users.

## Counting

Here are three sets of poster sized number that you can display on a wall:

In the writing numerals to 20 worksheets, you will find that the A version includes all numbers, B to E versions have about half the numbers included, F to I versions have about a third of the numbers included and the J version includes no numbers... just the lines to write them on. All versions include dashes under the numbers, so students have a reference for where to place the numbers.

## Rounding Numbers Worksheets

Not only does rounding further an understanding of numbers, it can also be quite useful in estimating and measuring. There are many every day situations where a precise number isn't needed. For example if you needed to paint your basement floor, you don't really need to find out the area to exact square inch since you don't buy paint that way. You get a good idea of the floor space (e.g. it is roughly 20 feet by 15 feet) then read the label on the can to see how many square feet the can of paint covers (which, by the way is also a rounded number and variable depending on the roller used, the porosity of the floor, etc.) and buy enough cans to cover your floor.

## Roman Numerals Worksheets

This is about as "old school" as you can get. Put on your tunica and pick up your scutum to tackle the worksheets on Roman Numerals. Below, you will see options for standard and compact forms. The standard form Roman Numeral math worksheets include numerals in the commonly-taught version where 999 is CMXCIX (i.e. write the numeral one place value at a time). The compact versions are for those who want more of a challenge where the Roman numerals are written in as concise a version as possible. In the compact version, 999 is written as IM (i.e. one less than 1000).

## Factors and Factoring Worksheets

What would factoring be without some factoring trees? They are probably the most elegant and convenient way to find the prime factors of a number, but they take a little practice, which is where we come in. The worksheets below are of two types. The first is finding all of the factors of a number. This is great for students who know their multiplication/division facts. If they don't, they might find this a little frustrating, so go back and work on that first. The second type is finding prime factors which we've chosen to do with tree diagrams. Among other things, this is a great way to find prime numbers and to practice divisibility rules.

## Binary Numbers Worksheets

The binary number system has broad applications, but it is most known for its predominance in computer architecture. Learning about the binary system not only encourages higher order thinking, but it also prepares students for further studies in mathematics and computer studies. The chart below may be useful for students who need some help lining things up and learning about place value as it relates to the binary system. We included a base 10 number column, so you can use the chart for converting between decimal and binary systems.

Binary Place Value Chart

This mystery number trick below is actually based on binary numbers. As you may know, each place in the binary system is a power of 2 (1, 2, 4, 8, 16, etc.). Since every decimal (base 10) number can be expressed as a binary number, each decimal number can therefore be expressed as a sum of a unique set of powers of 2. It is this concept that makes this trick work. You might notice that the largest decimal number on the cards is 63 which is also the largest 6-digit binary number (111111). The target position on each version of the mystery number trick contains the powers of 2 associated with the first 6 place values in the binary system (1, 2, 4, 8, 16, 32). Each of the 6 cards represents a specific place value. All 32 numbers on each card contain a 1 in the associated place when written in binary. Basically, when the "friend" identifies the cards that contain the mystery number, they are giving you a binary number that simply needs converting into a decimal number. Just for fun, we mixed up the numbers on the cards and the target position on versions C to J. Version A includes numbers in ascending order and version B includes numbers in descending order.