Question

$12 + 29 + 37 + 17 = 90$

1. find the missing number that makes the equation true.

$18 - 10 = 9 - 1$
$35 + 30 = 45 + \underline{}$

Explanation:

Step1: Calculate left side of first eq

$18 - 10 = 8$

Step2: Solve for missing value (first eq)

Let $x$ = missing number. $9 - x = 8 \implies x = 9 - 8 = 1$

Step3: Calculate left side of second eq

$35 + 30 = 65$

Step4: Solve for missing value (second eq)

Let $y$ = missing number. $45 + y = 65 \implies y = 65 - 45 = 20$

Answer:

For $18 - 10 = 9 - \underline{\quad}$: 1
For $35 + 30 = 45 + \underline{\quad}$: 20