InspirationzStore Photography - Math photography - mathematics equations calculator - for maths nerd teacher geek tutor student - T-Shirts - Adult Birch-Gray-T-Shirt XL (ts_113081_21) Adult and youth sizes are a blend of 50% cotton, 50% polyester. Toddler sizes are 100% cotton. Available in white, grey, light blue or pale pink. Custom printed image applied. Washing instructions: Do not use bleach, dry on low heat, turn inside out