Question

34+23. 57-20. 94-23. Для марьяма)​

Answer 1

$34 + 23 = (30 + 20) + (4 + 3) = 50 + 7 = 57 \\ 57 - 20 = (50 - 20) + 7 = 37 \\ 94 - 23 = (90 - 20) + (4 - 3) = 70 + 1 = 71$