Article in English: " Subtracting 1 from a number takes you backwards 1 number. For example, 4 - 1 = 3. For instance, you add the doubles 5 + 5 to get 10. Just write the equation backward to get 10 - 5 = 5.  If 5 + 5 = 10, then 10 - 5 = 5. If 2 + 2 = 4, then 4 - 2 = 2. For example:  3 + 1 = 4 1 + 3 = 4 4 - 1 = 3 4 - 3 = 1 For example, ___ + 1 = 6 (the answer is 5). This also sets the foundation for algebra and beyond.  Subtract the numbers in the 1s column and bring down the number in the 10s column. 32 = 3 10s and 2 1s. 64 = 6 10s and 4 1s. 96 = __ 10s and __ 1s. You want to subtract 42 - 37. You start by trying to subtract 2 - 7 in the 1s column. However, that doesn't work! Borrow 10 from the 10s column and put it into the 1s column. Instead of 4 10s, you now have 3 10s. Instead of 2 1s, you now have 12 1s. Subtract your 1s column first: 12 - 7 = 5. Then, check the 10s column. Since 3 - 3 = 0, you don't have to write 0. Your answer is 5.

Summary in Indonesian:
Mulailah dengan "mundur 1 angka. Pelajari pengurangan bilangan ganda. Hafalkan fact family. Carilah angka yang hilang. Hafalkan fakta pengurangan hingga 20. Berlatihlah mengurangkan angka 1-digit dari angka 2-digit tanpa meminjam. Berlatihlah nilai tempat untuk mempersiapkan diri mengurangkan dengan meminjam. Kurangkan dengan meminjam.