hand sketched grunge noise dirt scratch random cartoon shapes textured background in stop motion stock video - 黑板 個影片檔及 b 捲影像00:09噪音
person, hands and writing on glass board in schedule planning, brainstorming or tasks at the office. closeup of employee in project plan, agenda or reminder for company goals or mission at workplace - 黑板 個影片檔及 b 捲影像00:06辦公室
glass wall, hands writing and planning, brainstorming and math equation in office. strategy, idea and person with marker on board for business project, formula and financial analysis of information - 黑板 個影片檔及 b 捲影像00:11
close-up of the hand of a middle-aged man plotting a graph to show the relative speed at which the planets in our galaxy travel around the sun relative to the distance of their orbits from the sun (m equals mercury, v equals venus etc.) with chalk. - 黑板 個影片檔及 b 捲影像00:17地球
shot of empty classroom with chairs under desks in elementary school. school during vacation or holidays, a teaching classroom without students during a term break or the end of semester in kindergart - 黑板 個影片檔及 b 捲影像00:12
business people, planning and board for idea, strategy or problem solving with corporate team. diversity, meeting and group of professional men and women in discussion for solution, vision or project - 黑板 個影片檔及 b 捲影像00:15辦公室
profile view close-up sequence showing the hand of a middle-aged man with a watch writing illegibly with chalk on an old-fashioned blackboard in a room lit with natural light, uk. - 黑板 個影片檔及 b 捲影像00:18
two coworkers brainstorm in modern office at night, using sticky notes on a glass wall to organize ideas and plan tasks. planning, leadership, teamwork and creative problem solving. - 黑板 個影片檔及 b 捲影像00:16
hand sketched grunge noise dirt scratch random cartoon shapes textured background in stop motion stock video 4k stock video - 黑板 個影片檔及 b 捲影像00:09
business man, planning and writing on glass board or window for coding, math and formula solution at tech company. young professional drawing numbers, problem solving and information technology idea - 黑板 個影片檔及 b 捲影像00:12
sequence showing three close-up shots of a middle-aged man drawing the axis of a simple graph with chalk onto an old-fashioned, free-standing blackboard, uk. - 黑板 個影片檔及 b 捲影像00:20
green mock up blank vertical billboard on the city street for advertisement in bangkok, thailand - 黑板 個影片檔及 b 捲影像00:31廣告
hand sketched grunge noise dirt scratch random cartoon shapes textured background in stop motion stock video - 黑板 個影片檔及 b 捲影像00:10
classroom, education and teaching with learning, teacher giving lesson with students and whiteboard with scholarship. science class, black woman talking and young children in elementary school - 黑板 個影片檔及 b 捲影像00:13
abstract math equations and geometry formulas on black background for education and science - 黑板 個影片檔及 b 捲影像00:12數學符號
b/w 1920s boy doing math problems at chalkboard as other boy watches in vocational school / newsreel - 黑板 個影片檔及 b 捲影像00:15
