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LEGO Missing Piece Checker

Rule out the usual hiding places first. If the piece really is gone, check the set piece by piece and leave with the element ID LEGO asks for, or a link to buy the part.

Computer Science & AI 3-5 Replacement Pack

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45546 Computer Science & AI 3-5 Replacement Pack

212 pieces in 54 part and color combinations, plus 4 minifigures.

The piece count includes the 12 parts inside the set's minifigures, which this inventory lists separately. Spare parts are counted in neither figure.

Before you call it missing

Builders who report a missing piece often find it in one of these places. Tick each one off as you look.

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Piece checklist

White 40 pieces

  • Brick 2 x 2 White Part 3003 Element 6552095 or 6548256 ×4
  • Brick Sloped 33° 3 x 1 White Part 4286 Element 6632142 or 428601 ×4
  • Brick Special 1 x 2 with Pin - Bottom Stud Holder White Part 44865 Element 6406522 ×4
  • Plate Round 4 x 4 with Pin Hole White Part 60474 Element 6564904 or 4515347 ×4
  • Plate Round Corner 3 x 3 with 2 x 2 Round Cutout White Part 68568 Element 6552185 or 6339103 ×4
  • Plate Special 1 x 2 with Three Teeth [Tri-Tooth] White Part 15208 Element 6046381 ×4
  • Technic Brick 1 x 4 [3 Pin Holes] White Part 3701 Element 6601913 or 370101 ×4
  • Technic Brick 1 x 8 [7 Pin Holes] White Part 3702 Element 4582543 or 370201 ×4
  • Technic Brick 2 x 4 with 4 Pin Holes, 2 Pins White Part 112174 Element 6598035 ×2
  • Technic Brick 5 x 6 Right Angle Double White Part 7469 Element 6548852 ×2
  • Tile Round 2 x 2 with Black Circle, White Circles / Eye Print White Part 14769pr9967 Element 6522844 ×4

Black 28 pieces

  • Brick Special 2 x 2 with Pin and Axle Hole Black Part 6232 Element 6365577 or 6070692 ×4
  • Brick Special 2 x 4 with 3 Axle Holes Black Part 39789 Element 6244917 ×4
  • Plate Special 2 x 2 with Rubber Foot Black Part 109373 Element 6492701 ×4
  • Pulley, 2-Stage Black Part 7335 Element 6598041 ×4
  • Technic Axle 4 Black Part 3705 Element 370526 ×2
  • Tile Round 2 x 4 Black Part 66857 Element 6331483 ×4
  • Wedge Plate 4 x 6 Cut Corners Black Part 32059 Element 4129572 ×2
  • Wheel Smooth 24 x 14mm with Pin Hole Black Part 5253 Element 6482581 ×4

Dark Purple 24 pieces

  • Bracket 1 x 2 - 2 x 2 Dark Purple Part 44728 Element 6334093 or 4277936 ×8
  • Brick 2 x 2 Dark Purple Part 3003 Element 4653960 or 4589613 ×4
  • Brick 2 x 4 Dark Purple Part 3001 Element 4626935 or 4589602 ×4
  • Brick 2 x 6 Dark Purple Part 2456 Element 6147004 or 4589615 ×2
  • Brick Sloped 33° 3 x 2 Dark Purple Part 3298 Element 6055875 or 4224864 ×4
  • Plate 2 x 8 Dark Purple Part 3034 Element 6109931 ×2

Dark Turquoise 24 pieces

  • Bracket 1 x 2 - 2 x 2 Inverted Dark Turquoise Part 99207 Element 6513766 ×4
  • Brick 2 x 2 Dark Turquoise Part 3003 Element 6314091 or 4120399 ×4
  • Brick 2 x 4 Dark Turquoise Part 3001 Element 6249422 or 6235115 ×4
  • Plate Round Corner 3 x 3 with 2 x 2 Round Cutout Dark Turquoise Part 68568 Element 6323161 ×4
  • Technic Brick 1 x 2 [1 Pin Hole] Dark Turquoise Part 3700 Element 6345402 or 4140338 ×4
  • Tile Special Round 2 x 2 with Hole Dark Turquoise Part 15535 Element 6491435 ×4

Coral 22 pieces

  • Brick 2 x 2 Coral Part 3003 Element 6422920 ×4
  • Plate 2 x 4 Coral Part 3020 Element 6305455 ×4
  • Plate Special 1 x 4 x 2/3 with 1 x 2 Bottom Cutout Coral Part 7769 Element 6598033 ×4
  • Technic Axle Connector Smooth [with x Hole + Orientation] Coral Part 59443 Element 6544409 ×4
  • Technic Brick 1 x 2 with Axle Hole Type 1 [+ Opening] and Bottom Pin Coral Part 32064a Element 6439447 ×4
  • Tile 1 x 6 with Groove Coral Part 6636 Element 6425367 or 6258096 ×2

Light Bluish Gray 20 pieces

  • Brick Special 2 x 4, with 2 x 2 Brick with Top Pin and 1 x 2 Side Plates Light Bluish Gray Part 30592 Element 6301425 or 6278504 ×2
  • Plate Round 2 x 2 with Rounded Bottom [Boat Stud] Light Bluish Gray Part 2654 Element 4278273 or 4276273 ×8
  • Plate Special 2 x 2 x 2/3 with Axle Hole and Grill on Sides (Haybale) Light Bluish Gray Part 71752 Element 6609654 ×8
  • Technic Axle 5 Light Bluish Gray Part 32073 Element 32073194 or 4211639 ×2

Yellow 18 pieces

  • Technic Axle 3 Yellow Part 4519 Element 6130007 ×6
  • Technic Pin without Friction Ridges Lengthwise Yellow Part 3673 Element 6331822 ×12

Trans-Purple 12 pieces

  • Brick Round 2 x 2 D. Tube with 45° Elbow and Axle Holes (Crossholes) at Each End [LONG] Trans-Purple Part 5489 Element 6609651 ×4
  • Brick Sloped 45° 2 x 1 with Bottom Pin Trans-Purple Part 3040b Element 6609649 or 3040126 ×8

Trans-Clear 6 pieces

  • Brick Round 2 x 2 with Axle Hole Trans-Clear Part 3941 Element 6514281 or 6273152 ×6

Red 4 pieces

  • Brick 2 x 4 Red Part 3001 Element 300121 ×2
  • Technic Rubber Belt Medium [24mm ID] [Round Cross Section] Red Part 85544 Element 4544145 or 4544143 ×2

Trans-Orange 4 pieces

  • Wave / Flame Rounded with Base Rim Trans-Orange Part 6126b Element 6167741 or 4261397 ×4

Blue 2 pieces

  • Brick 2 x 4 Blue Part 3001 Element 300173 or 300123 ×2

Bright Light Orange 2 pieces

  • Brick 2 x 4 Bright Light Orange Part 3001 Element 6100027 or 4645053 ×2

Green 2 pieces

  • Brick 2 x 4 Green Part 3001 Element 4106356 or 300128 ×2

Medium Lavender 2 pieces

  • Brick 2 x 4 Medium Lavender Part 3001 Element 6013583 or 4655173 ×2

Tan 2 pieces

  • Technic Gear 20 Tooth Double Bevel with Axle Hole Type 1 [+ Opening] Tan Part 18575 Element 6346517 or 6084724 ×2

Minifigures 4 figures

  • Monochrome Bright Green Minifigure, checked as a whole figure ×1
  • Monochrome Red, 28621 Head Minifigure, checked as a whole figure ×1
  • Monochrome Blue Minifigure, checked as a whole figure ×1
  • Monochrome Bright Light Orange, 28621 Head Minifigure, checked as a whole figure ×1

Tick each piece as you find it, or mark it missing.

When a piece really is missing

Ask LEGO

LEGO takes requests for pieces missing from a new set through its customer service site. The form asks for the set number and each piece's element ID, the number printed beside the piece in the parts list at the back of the instructions. This checker lists both.

Request a replacement from LEGO

Buy the piece

Mark a piece missing and your list links it to an eBay search for that part, which also covers pieces from older or second-hand sets.

Keep a record

Copy or download your missing list (the CSV opens in any spreadsheet), or print the whole checklist and tick pieces off on paper. Your marks stay in this browser, so you can check a big set over several sittings.

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