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Surface area from a net worksheets

A net is a box laid flat, and every one of its faces is out in the open where a child can point at it. These free printable worksheets show only the unfolded net and ask for the surface area — the on-ramp to the standard before the closed solid arrives.

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Surface area from a net
Surface area from a net worksheet — Edges to 20 cm, free printable with answer key

The answer key prints on a separate page.

What's on this sheet

The mixed surface-area sheets alternate between the solid and the net; this one never draws the closed box at all. That is the whole point of it. A child who cannot yet hold three hidden faces in their head does not have to: all six rectangles are drawn flat, and the work is to see them as three matching pairs and add.

Why this sheet works

Only three edge lengths are printed on the cross, because that is what a box has, and the six faces are built from them. Front and back share a size, left and right share a size, top and bottom share a size — noticing that is what turns a long six-rectangle addition into 2(wd + wh + dh). Children fresh from volume will reach to multiply all three numbers together, and the flat figure is the clearest place to catch that.

How this one works

One question from this sheet, worked through a step at a time.

Surface area of a 9 × 10 × 14 box

9 × 10 × 14 cm
front and back:2 × 9 × 14 =252
front and back:2 × 9 × 14 =252
the two sides:2 × 10 × 14 =280
front and back:2 × 9 × 14 =252
the two sides:2 × 10 × 14 =280
top and bottom:2 × 9 × 10 =180
front and back:2 × 9 × 14 =252
the two sides:2 × 10 × 14 =280
top and bottom:2 × 9 × 10 =180
total:712
  1. A net lays all six faces out flat, so none of them is hidden — which is the whole reason a net is easier than the solid. They still come in three PAIRS.
  2. Front and back are 9 by 14, and they are identical — so that pair is 2 × 9 × 14 = 252.
  3. The two sides are 10 by 14, and they are identical — so that pair is 2 × 10 × 14 = 280.
  4. Top and bottom are 9 by 10, and they are identical — so that pair is 2 × 9 × 10 = 180.
  5. Three pairs, six faces, none missed: 252 + 280 + 180 = 712 square cm.

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