Subtracting a negative number
Rewrite every subtraction as an addition, see subtracting a negative on the line, and work two-digit sums in tens and ones.
- إيران: الصف ٧
- أوكرانيا: الصف ٦
- ألمانيا: الصف ٥
لم يُترجَم هذا المختبر إلى هذه اللغة بعد.
الدليل
This studio follows the Iranian Grade 7 lessons on adding and subtracting integers. The book always rewrites a subtraction as an addition first: ٣ − ٧ = ٣ + (−٧).
A عدد سالب such as −٥ is the opposite of 5. The opposite of −٥ is 5, so −(−٥) = ٥.
Subtracting a negative number means adding its opposite: −٤ − (−٥) = −٤ + ٥ = ١. On the line, instead of hopping left we hop 5 to the right.
You can work two-digit numbers in tens and ones: ٣٤ − ٢٧ = (٣٠ − ٢٠) + (٤ − ٧) = ١٠ + (−٣) = ٧.