You can use 'round to the nearest 10' to work out the difference between 39 and 67. First, add 1 to 39 to get 40. Then, add 27 to get 67. So, the total difference is 1 + 27, which is 28.
You can use 'round to the nearest 10' strategy to help work out your answer. Or you can look another strategy in the Next hint.
You could also 'compensate' to work out the difference between 39 and 67. First, add 30 to 39 to get 69. This number is larger than 67. So, take away the extra 2 from the 30 to get the answer 28.
You can use 'compensate' strategy to help work out your difference. Or you can look another strategy in the Previous hint.