Funny 18th Birthday Math Gift 18 Years Old Algebra Equation by modernmerch Unisex T-shirt, Sweatshirt, Hoodie, Long Sleeve Tee
Funny 18th Birthday Math Gift 18 Years Old Algebra Equation by modernmerch Unisex T-shirt, Sweatshirt, Hoodie, Long Sleeve Tee
Statement Apparel – Premium Quality, Printed on Demand
First impression? Fire. Tenth wash? Still fire. Printed directly on Gildan® cotton with pro-grade DTG ink that bonds to the fiber. No cracking, ever.
📸 Don’t let the mockup fool you – this isn’t just a tee. Get this design on 4 styles: T-Shirt, Long Sleeve, Sweatshirt & Hoodie. You pick, we produce. Simple as that.
Why You’ll Love It
- 🎨 Print That Pops – DTG-printed directly into the fabric. No cracking, no peeling – just bold, vivid color.
- 🧵 Fabric That Delivers – Gildan® Ultra Cotton & Heavy Blend. Soft, durable, certified low-impact dyes.
- 👕 Comfort First, Always – Taped neck, reinforced shoulders, tear-away tag. Built for all-day wearability.
- 🇺🇸 Sustainably Sourced – US Cotton Trust Protocol. From farm to fabric – responsible at every step.
What It’s Made Of
- T-Shirt & Long Sleeve: 100% US cotton, 5.3–6 oz – soft, breathable, classic fit.
- Sweatshirt & Hoodie: 50/50 Heavy Blend (8 oz) – pill-resistant with spandex cuffs & waistband.
- Sport Grey uses a 90/10 cotton/poly blend for its signature heathered tone.
Pick Your Color & Size
Find your size and pick your color – it’s that easy:
Available Colors
Gildan 5000 — Unisex T-Shirt
| Size | Length | Bust |
|---|---|---|
| S | 28 in (71.1 cm) | 36 in (91.4 cm) |
| M | 29 in (73.7 cm) | 40 in (101.6 cm) |
| L | 30 in (76.2 cm) | 44 in (111.8 cm) |
| XL | 31 in (78.7 cm) | 48 in (121.9 cm) |
| 2XL | 32 in (81.3 cm) | 52 in (132.1 cm) |
| 3XL | 33 in (83.8 cm) | 56 in (142.2 cm) |
| 4XL | 34 in (86.4 cm) | 60 in (152.4 cm) |
Gildan 2400 — Unisex Long Sleeve Tee
| Size | Length | Bust | Sleeve |
|---|---|---|---|
| S | 28 in (71 cm) | 36 in (92 cm) | 33.5 in (85 cm) |
| M | 29 in (74 cm) | 40 in (102 cm) | 35 in (89 cm) |
| L | 30 in (76 cm) | 44 in (112 cm) | 36.5 in (93 cm) |
| XL | 31 in (79 cm) | 48 in (122 cm) | 38 in (97 cm) |
| 2XL | 32 in (81 cm) | 52 in (132 cm) | 39.5 in (100 cm) |
| 3XL | 33 in (84 cm) | 56 in (142 cm) | 39.5 in (100 cm) |
| 4XL | 34 in (86 cm) | 60 in (152 cm) | 39 in (99 cm) |
Gildan 18000 — Unisex Sweatshirt
| Size | Length | Bust | Sleeve |
|---|---|---|---|
| S | 27 in (68.6 cm) | 40 in (101.6 cm) | 33.5 in (85.09 cm) |
| M | 28 in (71.1 cm) | 44 in (111.8 cm) | 34.5 in (87.63 cm) |
| L | 29 in (73.7 cm) | 48 in (121.9 cm) | 35.5 in (90.17 cm) |
| XL | 30 in (76.2 cm) | 52 in (132.1 cm) | 36.5 in (92.71 cm) |
| 2XL | 31 in (78.7 cm) | 56 in (142.2 cm) | 37.5 in (95.25 cm) |
| 3XL | 32 in (81.3 cm) | 60 in (152.4 cm) | 38.5 in (97.79 cm) |
| 4XL | 33 in (83.8 cm) | 64 in (162.6 cm) | 39.5 in (100.33 cm) |
Gildan 18500 — Unisex Hoodie
| Size | Length | Bust |
|---|---|---|
| S | 27 in (68.6 cm) | 40 in (101.6 cm) |
| M | 28 in (71.1 cm) | 44 in (111.8 cm) |
| L | 29 in (73.7 cm) | 48 in (121.9 cm) |
| XL | 30 in (76.2 cm) | 52 in (132.1 cm) |
| 2XL | 31 in (78.7 cm) | 56 in (142.2 cm) |
| 3XL | 32 in (81.3 cm) | 60 in (152.4 cm) |
| 4XL | 33 in (83.8 cm) | 64 in (162.6 cm) |
- Pick your color from the chart above.
- Choose your size using the size guide.
- Add to cart – we’ll handle the rest!
Shipping & Delivery
- ✅ Production Time: 1–3 business days.
- 📦 US Delivery: 3–7 business days.
- ⚡ US Rush Option: 3–5 business days.
- 🌍 Rest of World: 1–2 weeks.
Every item is made to order just for you. Please verify your size using the chart above. We can’t accept returns for sizing errors, but we’re always here to help if something isn’t right.
🛒 Find your next favorite at HolyTeesCo.com. Style, comfort, quality – guaranteed.