Tafuta marengo wa umbo. Andika pia to kipenefe cha mistari khuslataha.

$$
90255 - 740 = 89515
$$
Jibu: $\boxed{89515}$

$$
68152 - 66384 = 1768
$$
Jibu: $\boxed{1768}$

$$
165 \times 83 = 13695
$$
Jibu: $\boxed{13695}$

$$
684 \div 12 = 57
$$
Jibu: $\boxed{57}$

$$
\frac{1}{2} + \frac{1}{2} = \frac{1+1}{2} = \frac{2}{2}
$$

$$
\frac{2}{2} = 1
$$
Jibu: $\boxed{1}$

$$
\frac{7}{8} - \frac{1}{8} = \frac{7-1}{8} = \frac{6}{8}
$$

$$
\frac{6}{8} = \frac{3}{4}
$$
Jibu: $\boxed{\frac{3}{4}}$

$$
\frac{1}{2} \times \frac{1}{2} = \frac{1 \times 1}{2 \times 2} = \frac{1}{4}
$$
Jibu: $\boxed{\frac{1}{4}}$

$$
\frac{1}{2} \div \frac{1}{2} = \frac{1}{2} \times \frac{2}{1} = \frac{2}{2}
$$

$$
\frac{2}{2} = 1
$$
Jibu: $\boxed{1}$

$$
45.90 - 83.67 = -37.77
$$
Jibu: $\boxed{-37.77}$

$$
504 \div 28 = 18
$$
Jibu: $\boxed{18}$

    $$
    P = 4 \times 4 \text{ sm} = 16 \text{ sm}
    $$
    Jibu: $\boxed{16 \text{ sm}}$

*   **b) Umbo la mstatili (rectangular prism) lenye vipimo 5 sm, 4 sm, 4 sm.**
    Kutokana na kazi yako, inaonekana unatafuta jumla ya mizingo ya nyuso mbili kuu (kwa mfano, uso wa mbele na uso wa juu).

    $$
    P_{\text{mbele}} = 2 \times (5 \text{ sm} + 4 \text{ sm}) = 2 \times 9 \text{ sm} = 18 \text{ sm}
    $$

    $$
    P_{\text{juu}} = 2 \times (5 \text{ sm} + 4 \text{ sm}) = 2 \times 9 \text{ sm} = 18 \text{ sm}
    $$

    $$
    P_{\text{jumla}} = 18 \text{ sm} + 18 \text{ sm} = 36 \text{ sm}
    $$
    Jibu: $\boxed{36 \text{ sm}}$

*   **c) Pembetatu yenye pande 7 sm, 5 sm, 8 sm.**

    $$
    P = 7 \text{ sm} + 5 \text{ sm} + 8 \text{ sm} = 20 \text{ sm}
    $$
    Jibu: $\boxed{20 \text{ sm}}$

*   **d) Mraba wenye upande wa 13 sm.**

    $$
    P = 4 \times 13 \text{ sm} = 52 \text{ sm}
    $$
    Jibu: $\boxed{52 \text{ sm}}$