Adding and subtracting uneven decimals
The question
15.0 − 14.95
4910 15.00 14.95 0.5
- 15.0 − 14.95. Line up the decimal points, not the right-hand ends.
- 15.0 has fewer figures after the point, so fill the gap with a zero: 15.00. A zero on the end of a decimal changes nothing.
- 0 is too small to take 5 from, so a ten comes across from the left: this column now holds 10. 10 − 5 = 5.
- 0 is too small to take 9 from, so a ten comes across from the left: this column now holds 9. 9 − 9 = 0. A nothing at the front is not written, so the answer starts one place along.
- This column gave a ten to the right, so it is now 4, not 5. 4 − 4 = 0.
- 1 take away 1 leaves nothing — and a nothing at the front is not written, so the answer starts one place along.
- The point in the answer comes straight down. 15.0 − 14.95 = 0.05.
How it works.
- 01
15.0 − 14.95. Line up the decimal points, not the right-hand ends.
- 02
15.0 has fewer figures after the point, so fill the gap with a zero: 15.00. A zero on the end of a decimal changes nothing.
- 03
0 is too small to take 5 from, so a ten comes across from the left: this column now holds 10. 10 − 5 = 5.
- 04
0 is too small to take 9 from, so a ten comes across from the left: this column now holds 9. 9 − 9 = 0. A nothing at the front is not written, so the answer starts one place along.
- 05
This column gave a ten to the right, so it is now 4, not 5. 4 − 4 = 0.
- 06
1 take away 1 leaves nothing — and a nothing at the front is not written, so the answer starts one place along.
- 07
The point in the answer comes straight down. 15.0 − 14.95 = 0.05.