What does it mean to estimate?

The students were presented with a math task to explore estimation. Estimating means roughly calculating or judging a number or value.

‘Estimation skills provide students with an ability that instils confidence with number. Everyday life requires estimations and approximations such as rounding to the nearest ten, hundred or thousand (Booker, Bond, Sparrow & Swan, 2010).’

A row of dice was placed at the edge of the green rectangle. First, we counted to find out how many we needed on one side of the shape. Then, a question was presented.

How many dice will we need if we were going right around the edge of the rectangle?

The children used their whiteboards to write their estimates (best guess). Then, we recorded these estimates on the board.

Next, we added a few more around the perimeter of the shape.

The children could change their estimate based on the new information presented. Finally, we placed the dice around the edge of the rectangle to check our estimations.

We needed 22 dice to go around the rectangle!

We had a smaller rectangle and so we tried to find out how many dice would go around the edge of the smaller rectangle.

We used an empty number line to find out the estimate that was the closest to the actual number. 

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