simplify 2sqrt(20)-sqrt(20)+3sqrt(20)-2sqrt(45)
Let's simplify: 2×20 -20 + 3×20 -2×45
ⓘ We look for the largest square dividing 20, 4 = 22, and take it out of the root: 20 = 4×5 = 4×5 = 2×5■We look for the largest square dividing 45, 9 = 32, and take it out of the root: 45 = 9×5 = 9×5 = 3×5
2×2×5 -2×5 + 3×2×5 -2×3×5
ⓘ Multiplications are done before additions and subtractions: 2×2 = 4, 3×2 = 6, 2×3 = 6
4×5 -2×5 + 6×5 -6×5
ⓘ Like terms are grouped by adding their coefficients: 4×5 -2×5 + 6×5 -6×5 = 2×5
▶Simplified form:   2×5
The numeric value of: 2×5 is:
2×≈ 2.2361
▷ ≈ 4.4721