both 40 and 400 have one because there is no "." the 0.7000 has four SF because you know that the first three digits after the seven are exact while the last zero could be rounded. the concept is a little tough to get but once you do its pretty simple.
3 significant figures.
300x400mm = 120000mm 1cm = 10mm 1in = 2.54cm 120000mm x 1cm/10mm = 12000cm 12000cm x 1in/2.54cm = 4700in (Rounded to two significant figures.)
45.0300mm has six significant figures. A significant figure is any non-zero digit or any embedded or trailing zero. Leading zeros are not significant.
There are 400 cm in 4000 mm. This is because 1 cm is equal to 10 mm, so to convert mm to cm you divide by 10.
40 cm = 400 mm 100 mm = 10 cm 100 cm = 1 metre
2 significant figures.
There are 3 significant figures in this number.
There are 6 significant figures in this length.
3 significant figures.
It has 2 significant figures. However, the fact that it is given as 2300 mm and not as 230 cm suggests that it is, in fact significant to 4 figures.
2 of them.
4
4. The zeroes to the left are not significant, the zero to the right, is.
111.009 mm rounded off to four significant figures is 111.0
3 of them.
The least number of significant figures in any number of the problem determines the number of significant figures in the answer.
300x400mm = 120000mm 1cm = 10mm 1in = 2.54cm 120000mm x 1cm/10mm = 12000cm 12000cm x 1in/2.54cm = 4700in (Rounded to two significant figures.)