0.4 Tablespoon to Teaspoon
0.4 tbsp = 1.2 tsp
= 5.9 ml | 0.2 fl oz | 0.0250 cups
Closest practical measure: 1 tsp + 1/4 tsp (a little less)
Australia: 0.4 tbsp = 1.6 tsp (20 ml tablespoon)
0.4 of a tablespoon is 1.2 teaspoons, just over one teaspoon. A tablespoon holds 3 level teaspoons, so 0.4 of it is 3 × 0.4 = 1.2 tsp (5.9 ml). Measure 1 level teaspoon plus a small pinch; the closest standard combination is 1 tsp + 1/4 tsp (1.25 tsp). A recipe scaler prints the decimal 0.4 tbsp when a batch has been scaled; the original was almost certainly 1 teaspoon or close to it.
Four-tenths of a tablespoon is 1.2 teaspoons or 5.9 ml. This is just over one teaspoon (1 tsp = 5 ml). Practically you would measure 1 teaspoon plus a small pinch (about 1/8 teaspoon = 0.125 tsp would put you at 1.125 tsp, close enough). Decimal-tablespoon quantities like 0.4 typically come from recipes scaled from a 5x or 10x batch where ingredients were normalised to decimals. In Australia, 0.4 of a 20 ml tablespoon is 1.6 metric teaspoons (8 ml).