# 2nd Grade Number Sense Resources

This is a hundreds chart, but with a twist. Every number in the hundreds chart has been multiplied by a random number [1,10]. Can you figure out the pattern? (See also Number Path, which explores the same idea on a normal hundreds chart.)

Arrange the digits 1-9 into three 3-digit numbers. Try to get the sum as close to 1000 as possible.

Use the given quantity to estimate the others. Use the sliders to adjust the size of the numbers (10 to 1000) and number of questions. Kindergartners might use this to talk about more/less, while 6th graders might have highly sophisticated approaches involving unit rate.

A random number of objects (between 0 and the upper limit you specify) flashes on the screen. Estimate how many you saw. Then display the picture again, reconsider your guess, and finally see the answer. Designed to develop solid connection between a number and how "big" it actually is.

An updated version of "How Many?" with a new feature: once you see the squares, you can arrange them into groups. Use this to connect estimation and quantity to skip counting. Or use it to have a conversation about multiplication or division.

This grid goes to 120. Click on the numbers to toggle the colors. Click on an arrow to turn the entire row or column red. Explore 1 or 10 more/less, patterns in skip counting or beyond.

Enter any number of hundreds, tens, and ones to see that number drawn in any of three ways. One way of using this is to help students see the difference between a digit and its value. For example, a student might say the number 63 has 60 tens and 3 ones. If you enter that in this applet, you can see a number represented as...

60 tens and 3 ones ("How I typed it")

6 hundreds and 3 ones ("Standard place value")

603 ones ("All ones")

Meant to help develop the idea of possible rounding outcomes by exploring the numbers on an interval of 10, 100, or 1000. Name numbers on an interval (and predict their location!) or drag a randomly generated number to the correct spot (with feedback on the placement provided).

Enter a whole number (under 1 million) and it will be shown as a bar partitioned along base-10 values. Use this for a visual demonstration of, for example, why 543 > 345, beyond "because 5 is bigger than 3".

Drag whole numbers to the correct locations on a (mostly) blank number line. Feedback provided. Adjust the upper limit for the size of the number and how many are placed on the line.

The purpose of this tool is to help students see the connection between (a modeled representation of ) expanded form and the digits that make up a number. Use the slider to select which places to use (ones and tens are required, but hundreds - for 2nd grade - and thousands - for 3rd grade - are optional). This program will then make a number by randomly choosing one base-ten block for each place (up to 9) that you choose. Once you click start, the number gets covered up by a purple rectangle that you reveal once you've had a chance to discuss what *might* be under it. Consider the following questions:

What's a number that might be under here?

What's a number that couldn't possibly be under here?

What's the smallest number that might be under here?

What's the biggest number that might be under here?

What's something that ALL possible numbers have in common?

Enter a number (up to 1000), then regroup it into ones, tens, and hundreds. See also "Making Tens." Designed to allow students to see lots of equivalent representations of numbers.

A random number (upper limit is adjustable) is generated and placed on a blank number line. Your job is to guess where it landed. Click "more info" to zoom in and refine your guess.