The experimental evidence that the electron exhibits wave-like characteristics was first provided by:

78.89 × 81.03 – (16.83)² + 8.33% of 9602.87 = ? – 50.23

1220 ÷ 61 ÷ 5 + 450 of 20% - 70 = √ ?

4261 + 8234 + 2913 + 8217 + 6283 + 4172 =?

25% of 400 + 3 × 10² = ?² 

104 × 21 ÷ 13 + ? % of 300 = 320 + 22

1549.8 ÷ 8.2 + 65.6 × 55 = (? × 4) + (42 × 30.5)

√( (664+ √(136+ √(59+ √(21+ √(7+ √81) ) ) ) ) ) = ?

[4(1/3) + 4(1/4)] × 24 – 62 = ?²

(5/7) of (7/11) of (3/5) of 52% of 4400 = ? - (44)² + (50)² - (62% of 1750) - (188 ÷ 9.4)

756 + 432 – 361 + ? = 990