To add numbers, you can line up the numbers vertically and then add the matching places together. This tutorial shows you how to add numbers vertically!

This Nrich low threshold high ceiling task is accessible to everyone. It gives children the chance to share the way they picture (visualize) numbers and their methods of counting. One of the key features of this task is that it can be interpreted differently, depending on the image, so that children can decide for themselves whether they are counting individual fruit, cartons of fruit... Therefore there may also be an opportunity for children to develop their estimation skills as well as appreciating different ways of counting.

The purpose of this task is for students to apply the concepts of mass, volume, and density in a real-world context. There are several ways one might approach the problem, e.g., by estimating the volume of a person and dividing by the volume of a cell.

This is a mathematical modeling task aimed at making a reasonable estimate for something which is too large to count accurately, the number of leaves on a tree.

In this problem, the variables a,b,c, and d are introduced to represent important quantities for this esimate: students should all understand where the formula in the solution for the number of leaves comes from. Estimating the values of these variables is much trickier and the teacher should expect and allow a wide range of variation here.

As written, this problem gives students all of the information they need to estimate the thickness of a soda can.

his is a version of ''How thick is a soda can I'' which allows students to work independently and think about how they can determine how thick a soda can is. The teacher should explain clearly that the goal of this task is to come up with an ''indirect'' means of assessing how thick the can is, that is directly measuring its thickness is not allowed.

The instructional resources cover attributes of different quadrilaterals with practice categorizing and drawing them.

This Nrich task is an unusual way to explore number patterns in a well-known context. The activity will reinforce the construction of the hundred square, and increase children's familiarity with the sequences contained within it. Using a common resource, such as a hundred square, is a good way for children to begin to use visualisation, which they may find quite difficult at first. The act of visualising in this problem tests children's understanding of how the number square is created.

This rich task is an excellent example of geometric concepts in a modeling situation and is accessible to all students. In this task, students will provide a sketch of a paper ice cream cone wrapper, use the sketch to develop a formula for the surface area of the wrapper, and estimate the maximum number of wrappers that could be cut from a rectangular piece of paper.

This short video and interactive assessment activity is designed to teach first graders an overview of rectangles, squares, circles and triangles.

This short video and interactive assessment activity is designed to teach second graders an overview of rectangles, squares, circles and triangles.

This short video and interactive assessment activity is designed to teach third graders an overview of rectangles, squares, circles and triangles.

This short video and interactive assessment activity is designed to give fifth graders an overview of rectangles, squares, circles and triangles.

This short video and interactive assessment activity is designed to teach second graders an overview of ellipses, trapezoids, rhombi, and polygons.

This short video and interactive assessment activity is designed to teach third graders an overview of ellipses, trapezoids, rhombi, and polygons.

This short video and interactive assessment activity is designed to give fifth graders an overview of quarter-circles and semi-circles.

This short video and interactive assessment activity is designed to teach third graders about determining whether lines are perpendicular.

This short video and interactive assessment activity is designed to teach third graders an overview of quadrilaterals.